I tried to test some example application in DD5.1,but it's really hard to do this because the simulator will throw error when start the application.
every application has the same error:

Personal Voice Browser Version 5.1 Copyright (c) 2004-2010, Avaya
Error(0x8004503a) unable to set audio input
App Log: EVENT Id(2) Label() Msg(Error: error.badfetch , Error fetching document http://localhost:8080/DTMFToneMask/Start?call_classification=live_voice&sagecfhport=56304&sagecfhhost=LA090026&session___sessionid=sess7958605&session___vpconverseondata=)
Playing text " Your application is having a problem. The event ", Language (en-us), Gender (Female)
Playing text "error.badfetch", Language (en-us), Gender (Female)
Playing text " was caught ", Language (en-us), Gender (Female)
Playing text "    with message ", Language (en-us), Gender (Female)
Playing text "Error fetching document http://localhost:8080/DTMFToneMask/Start?call_classification=live_voice&sagecfhport=56304&sagecfhhost=LA090026&session___sessionid=sess7958605&session___vpconverseondata=", Language (en-us), Gender (Female)
Playing text " , Since no event handler was found, the application is exiting.       ", Language (en-us), Gender (Female)

any idea?

Try to use the Dialog Designer->Update Context and Generate Project menu options. If that still doesn't work, try to make a slight modification like moving a node in the call flow. Take a look into the trace.log for any error.

Actually, no error in trace. it stopped before callflow execute, i think it 's because of timeout, when invoke the Start node, it is very slow.
So i tried to modify the fetch timeout from 15s to 60s, then the problem is fixed. but it's really very slow to start the callflow, don't know why? but it never happen in DD 5.0.

Do you have this problem every time even Tomcat has already started? Can you post some logs from eclipse\plugins\com.avaya.sceavb\AVB\log\avblog.txt?

Yes, almost every time even tomcat already started.
AVB log(fetch timeout=15s):
avayaVXIRef:Waiting for call, enter command:avayaVXIRef:Personal Voice Browser Version 5.1 Copyright (c) 2004-2010, AvayaJun 25 17:45:00.671|39|0039-00000000|6672|FINE|Client|New call started on channel New call started on channel 39
Jun 25 17:45:00.671|39|0039-00000000|6672|FINE|Rec|osbrec.cpp:418:osbrec.cpp:418:AVBrecBeginSession entering...
Jun 25 17:45:00.671|39|0039-00000000|6672|FINE|Client|New call started for New call started for http://localhost:8080/TestRecord/Start?call_classification=live_voice&sagecfhport=43258&sagecfhhost=LA090026&session___sessionid=sess2075935&session___vpconverseondata=
Jun 25 17:45:00.781|39|0039-00000000|6672|FINE|Cache|SBinetFileStream.cpp:132:SBinetFileStream::Open: url=file://E:\\Eclipse3.5.2\\plugins\\com.avaya.sceavb_5.1.0.1101\\AVB\\data\\defaults.xml
Jun 25 17:45:00.781|39|0039-00000000|6672|FINE|Cache|Opening local file: E:\\Eclipse3.5.2\\plugins\\com.avaya.sceavb_5.1.0.1101\\AVB\\data\\defaults.xml size: 21315
Jun 25 17:45:00.796|39|0039-00000000|6672|FINE|Platform|ChannelImpl.cpp:3442:CChannelImpl::ReportURIFetchStatus: Fetched Document E:\\Eclipse3.5.2\\plugins\\com.avaya.sceavb_5.1.0.1101\\AVB\\data\\defaults.xml, Type=VXML, FetchTime=109, parseTime=0, from URL
Jun 25 17:45:00.796|39|0039-00000000|6672|FINE|Jsi|SBjsiFuncs.cpp:144:SBjsiCreateContext: entering
Jun 25 17:45:00.796|39|0039-00000000|6672|FINE|Jsi|SBjsiFuncs.cpp:179:SBjsiCreateContext: exiting: returned rc=0
Jun 25 17:45:00.875|39|0039-00000000|6672|FINE|Cache|SWIipAddress.cpp:729:SWIipAddress.cpp:729:Resolving ip addresses
Jun 25 17:45:00.875|39|0039-00000000|6672|FINE|Cache|SWIipAddress.cpp:736:Resolved address (0): 127.0.0.0
Jun 25 17:45:00.875|39|0039-00000000|6672|FINE|Cache|SWIsocket.cpp:217:connecting to 127.0.0.1
Jun 25 17:45:00.875|39|0039-00000000|6672|FINE|Cache|SWIsocket.cpp:326:Established Connection to 127.0.0.1
avayaVXIRef:Error(0x8004503a) unable to set audio inputJun 25 17:45:15.812|39|0039-00000000|6672|FINE|Cache|SBinetHttpStream.cpp:1332:SBinetHttpStream::getHeaderInfo: Waited 14937ms for HTTP response
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Cache|SBinetHttpStream.cpp:1338:SBinetHttpStream::getHeaderInfo: rc=51, HttpStatus=-1234
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Cache|Failed in GET with return code = 51
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Cache|SBinetHttpStream.cpp:638:Undefined HTTP status -1234 for url = http://localhost:8080/TestRecord/Start?call_classification=live_voice&sagecfhport=43258&sagecfhhost=LA090026&session___sessionid=sess2075935&session___vpconverseondata=
Jun 25 17:45:15.812|39|0039-00000000|6672|ERROR|Cache|Fetch time out when opening timed stream for url = http://localhost:8080/TestRecord/Start?call_classification=live_voice&sagecfhport=43258&sagecfhhost=LA090026&session___sessionid=sess2075935&session___vpconverseondata=. Timeout was = 15000|PAVB_00213|Arg[0]=http://localhost:8080/TestRecord/Start?call_classification=live_voice&sagecfhport=43258&sagecfhhost=LA090026&session___sessionid=sess2075935&session___vpconverseondata=|Arg[1]=15000
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Cache|Timed out fetching URL Timed out fetching URL http://localhost:8080/TestRecord/Start?call_classification=live_voice&sagecfhport=43258&sagecfhhost=LA090026&session___sessionid=sess2075935&session___vpconverseondata=
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Interpreter|DocumentParser.cpp:751:Failed to load document from URL http://localhost:8080/TestRecord/Start?call_classification=live_voice&sagecfhport=43258&sagecfhhost=LA090026&session___sessionid=sess2075935&session___vpconverseondata=
Jun 25 17:45:15.812|39|0039-00000000|6672|ERROR|Interpreter|error.badfetch.http.905 URI: http://localhost:8080/TestRecord/Start?call_classification=live_voice&sagecfhport=43258&sagecfhhost=LA090026&session___sessionid=sess2075935&session___vpconverseondata=|PAVB_03064|Arg[0]=905|Arg[1]=http://localhost:8080/TestRecord/Start?call_classification=live_voice&sagecfhport=43258&sagecfhhost=LA090026&session___sessionid=sess2075935&session___vpconverseondata=
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Interpreter|VXI::DoEvent - Enter
Jun 25 17:45:15.812|39|0039-00000000|6672|OFF|MsgId=2||Error: error.badfetch , Error fetching document http://localhost:8080/TestRecord/Start?call_classification=live_voice&sagecfhport=43258&sagecfhhost=LA090026&session___sessionid=sess2075935&session___vpconverseondata=
avayaVXIRef:EVENT Id(2) Label() Msg(Error: error.badfetch , Error fetching document http://localhost:8080/TestRecord/Start?call_classification=live_voice&sagecfhport=43258&sagecfhhost=LA090026&session___sessionid=sess2075935&session___vpconverseondata=)Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Prompt|Queuing TTS prompt - MIME type text/plain;charset=wchar_t Text:
Your application is having a problem. The event
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Prompt|Using ISO Language Code: en-US for TTS
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Prompt|Queuing TTS prompt - MIME type text/plain;charset=wchar_t Text: error.badfetch
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Prompt|Using ISO Language Code: en-US for TTS
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Prompt|Queuing TTS prompt - MIME type text/plain;charset=wchar_t Text: was caught

Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Prompt|Using ISO Language Code: en-US for TTS
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Prompt|Queuing TTS prompt - MIME type text/plain;charset=wchar_t Text:
with message
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Prompt|Using ISO Language Code: en-US for TTS
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Prompt|Queuing TTS prompt - MIME type text/plain;charset=wchar_t Text: Error fetching document http://localhost:8080/TestRecord/Start?call_classification=live_voice&sagecfhport=43258&sagecfhhost=LA090026&session___sessionid=sess2075935&session___vpconverseondata=
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Prompt|Using ISO Language Code: en-US for TTS
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Prompt|Queuing TTS prompt - MIME type text/plain;charset=wchar_t Text:
, Since no event handler was found, the application is exiting.

Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Prompt|Using ISO Language Code: en-US for TTS
Jun 25 17:45:15.812|39|0039-00000000|6672|FINE|Prompt|osbprompt.cpp:918:osbprompt.cpp:918:(no bargin: we cannot play)
avayaVXIRef:Barge-in EnabledavayaVXIRef:Playing text "
Your application is having a problem. The event ", Language (en-us), Gender (Female)avayaVXIRef:Barge-in EnabledavayaVXIRef:Playing text "error.badfetch", Language (en-us), Gender (Female)avayaVXIRef:Barge-in EnabledavayaVXIRef:Playing text " was caught
", Language (en-us), Gender (Female)avayaVXIRef:Barge-in EnabledavayaVXIRef:Playing text "
with message ", Language (en-us), Gender (Female)avayaVXIRef:Barge-in EnabledavayaVXIRef:Playing text "Error fetching document http://localhost:8080/TestRecord/Start?call_classification=live_voice&sagecfhport=43258&sagecfhhost=LA090026&session___sessionid=sess2075935&session___vpconverseondata=", Language (en-us), Gender (Female)avayaVXIRef:Barge-in EnabledavayaVXIRef:Playing text "
, Since no event handler was found, the application is exiting.
", Language (en-us), Gender (Female)Jun 25 17:46:03.578|39|0039-00000000|6672|FINE|Prompt|(bargin, we can play)
Jun 25 17:46:03.578|39|0039-00000000|6672|FINE|Prompt|osbprompt.cpp:918:osbprompt.cpp:918:(no bargin: we cannot play)
Jun 25 17:46:03.578|39|0039-00000000|6672|FINE|Prompt|(bargin, we can play)
Jun 25 18:00:02.593|-1||3076|FINE|client|LMloglevel.cpp:663:Log Setting XML processing time: (ms)0
Jun 25 18:00:02.671|-1||3076|FINE|client|LogManager.cpp:641:property file name=E:\\Eclipse3.5.2\\plugins\\com.avaya.sceavb_5.1.0.1101\\AVB/data/LogMsg.property

You are hitting the fetch timeout value of 15 seconds when it is trying to start your application.
Do you see any errors in your Tomcat logs ?
Did you upgrade your applications from 5.0 to 5.1?
Try to clean and rebuild the projects and restart tomcat.

I am also facing the same problem. below is the log

Personal Voice Browser Version 6.0 Copyright (c) 2004-2011, Avaya
uid_17:Oct 28 17:40:46.823|FINE|Client|New call started on channel New call started on channel 17
uid_17:Oct 28 17:40:46.824|FINE|Rec|osbrec.cpp:418:osbrec.cpp:418:AVBrecBeginSession entering...
uid_17:Oct 28 17:40:46.824|FINE|Client|New call started for New call started for http://localhost:8080/testproject/Start?call_classification=live_voice&sagecfhport=42586&sagecfhhost=GUREH-PGUPTA&session___sessionid=sess3723488&session___vpconverseondata=
uid_17:Oct 28 17:40:46.880|FINE|Cache|SBinetFileStream.cpp:132:SBinetFileStream::Open: url=file://D:\\Imp Doc\\dd\\eclipse\\plugins\\com.avaya.sceavb_6.0.0.0901\\AVB\\data\\defaults.xml
uid_17:Oct 28 17:40:46.880|FINE|Cache|Opening local file: D:\\Imp Doc\\dd\\eclipse\\plugins\\com.avaya.sceavb_6.0.0.0901\\AVB\\data\\defaults.xml size: 21315
uid_17:Oct 28 17:40:46.888|FINE|Platform|ChannelImpl.cpp:3510:CChannelImpl::ReportURIFetchStatus: Fetched Document D:\\Imp Doc\\dd\\eclipse\\plugins\\com.avaya.sceavb_6.0.0.0901\\AVB\\data\\defaults.xml, Type=VXML, FetchTime=0, parseTime=5, from URL
uid_17:Oct 28 17:40:46.888|FINE|Jsi|SBjsiFuncs.cpp:144:SBjsiCreateContext: entering
uid_17:Oct 28 17:40:46.889|FINE|Jsi|SBjsiFuncs.cpp:179:SBjsiCreateContext: exiting: returned rc=0
uid_17:Oct 28 17:40:46.904|FINE|Cache|SWIipAddress.cpp:729:SWIipAddress.cpp:729:Resolving ip addresses
uid_17:Oct 28 17:40:46.904|FINE|Cache|SWIipAddress.cpp:736:Resolved address (0): 127.0.0.0
uid_17:Oct 28 17:40:46.905|FINE|Cache|SWIsocket.cpp:217:connecting to 127.0.0.1
uid_17:Oct 28 17:40:46.905|FINE|Cache|SWIsocket.cpp:326:Established Connection to 127.0.0.1
uid_17:Oct 28 17:40:46.907|FINE|Cache|SBinetHttpStream.cpp:1332:SBinetHttpStream::getHeaderInfo: Waited 2ms for HTTP response
uid_17:Oct 28 17:40:46.907|FINE|Cache|SBinetHttpStream.cpp:1338:SBinetHttpStream::getHeaderInfo: rc=0, HttpStatus=404
uid_17:Oct 28 17:40:46.907|ERROR|Cache|HTTP Error for url = http://localhost:8080/testproject/Start?call_classification=live_voice&sagecfhport=42586&sagecfhhost=GUREH-PGUPTA&session___sessionid=sess3723488&session___vpconverseondata=, Method = GET, HttpStatus = 404, HTTPStatusDescription = Not found|HTTP Error for url = http://localhost:8080/testproject/Start?call_classification=live_voice&sagecfhport=42586&sagecfhhost=GUREH-PGUPTA&session___sessionid=sess3723488&session___vpconverseondata=, Method = GET, HttpStatus = 404, HTTPStatusDescription = Not found
uid_17:Oct 28 17:40:46.907|FINE|Interpreter|DocumentParser.cpp:751:Failed to load document from URL http://localhost:8080/testproject/Start?call_classification=live_voice&sagecfhport=42586&sagecfhhost=GUREH-PGUPTA&session___sessionid=sess3723488&session___vpconverseondata=
uid_17:Oct 28 17:40:46.907|ERROR|Interpreter|error.badfetch.http.404 URI: http://localhost:8080/testproject/Start?call_classification=live_voice&sagecfhport=42586&sagecfhhost=GUREH-PGUPTA&session___sessionid=sess3723488&session___vpconverseondata=|error.badfetch.http.404 URI: http://localhost:8080/testproject/Start?call_classification=live_voice&sagecfhport=42586&sagecfhhost=GUREH-PGUPTA&session___sessionid=sess3723488&session___vpconverseondata=
uid_17:Oct 28 17:40:46.909|FINE|Interpreter|VXI::DoEvent - Enter
uid_17:Oct 28 17:40:46.909|OFF|MsgId=2||Error: error.badfetch.http.404 , Error fetching document http://localhost:8080/testproject/Start?call_classification=live_voice&sagecfhport=42586&sagecfhhost=GUREH-PGUPTA&session___sessionid=sess3723488&session___vpconverseondata=
uid_17:Oct 28 17:40:46.909|FINE|Prompt|Queuing TTS prompt - MIME type text/plain;charset=wchar_t Text: Your application is having a problem. The event
uid_17:Oct 28 17:40:46.909|FINE|Prompt|Using ISO Language Code: en-US for TTS
uid_17:Oct 28 17:40:46.909|FINE|Prompt|Queuing TTS prompt - MIME type text/plain;charset=wchar_t Text: error.badfetch.http.404
uid_17:Oct 28 17:40:46.909|FINE|Prompt|Using ISO Language Code: en-US for TTS
uid_17:Oct 28 17:40:46.910|FINE|Prompt|Queuing TTS prompt - MIME type text/plain;charset=wchar_t Text: was caught
uid_17:Oct 28 17:40:46.910|FINE|Prompt|Using ISO Language Code: en-US for TTS
uid_17:Oct 28 17:40:46.910|FINE|Prompt|Queuing TTS prompt - MIME type text/plain;charset=wchar_t Text: with message
uid_17:Oct 28 17:40:46.910|FINE|Prompt|Using ISO Language Code: en-US for TTS
uid_17:Oct 28 17:40:46.910|FINE|Prompt|Queuing TTS prompt - MIME type text/plain;charset=wchar_t Text: Error fetching document http://localhost:8080/testproject/Start?call_classification=live_voice&sagecfhport=42586&sagecfhhost=GUREH-PGUPTA&session___sessionid=sess3723488&session___vpconverseondata=
uid_17:Oct 28 17:40:46.910|FINE|Prompt|Using ISO Language Code: en-US for TTS
uid_17:Oct 28 17:40:46.910|FINE|Prompt|Queuing TTS prompt - MIME type text/plain;charset=wchar_t Text: , Since no event handler was found, the application is exiting.
uid_17:Oct 28 17:40:46.910|FINE|Prompt|Using ISO Language Code: en-US for TTS
uid_17:Oct 28 17:40:46.910|FINE|Prompt|osbprompt.cpp:932:osbprompt.cpp:932:(no bargin: we cannot play)

Pradeep, have you read questions and suggestions posted by Shweta. Try to post detailed answers to continue discussion.