The call transfers fine from the blind call command. There definitely is a hold command being sent across to the app after the transfer, but that won't mess up your transfer, just will give you application errors. You do not need to do a disconnect after a transfer. You should review the app and see what it does after the transfer. From the logs, I don't see anything wrong with this application.
29/09/2014 15:33:09:966 DEBUG - 5E6B39D16AFCC2F5B29739A80519B1D0:/ScriptProV1 : CTICommand.setCallInfoVariableValues: State transferred
29/09/2014 15:33:09:968 DEBUG - 5E6B39D16AFCC2F5B29739A80519B1D0:/ScriptProV1 : CTICommand.execute: encrypted value is HeOhNXdyzSKLXU4S2Gp+n0rg5s413ONJU3SENtSUD4Q=
29/09/2014 15:33:09:968 DEBUG - 5E6B39D16AFCC2F5B29739A80519B1D0:/ScriptProV1 : VariableUtil.getVariableValue: Variable value is 12424
29/09/2014 15:33:09:968 DEBUG - 5E6B39D16AFCC2F5B29739A80519B1D0:/ScriptProV1 : CTICommand.execute: request to manager is
http://192.168.155.140:8080/aesconnector/Hold?callid%3D12424%26extension%3D6401&k=HeOhNXdyzSKLXU4S2Gp%2Bn0rg5s413ONJU3SENtSUD4Q%3D
29/09/2014 15:33:09:968 DEBUG - 5E6B39D16AFCC2F5B29739A80519B1D0:/ScriptProV1 : CTICommand.execute: setting session cookie to 5E6B39D16AFCC2F5B29739A80519B1D0:/ScriptProV1
29/09/2014 15:33:09:972 DEBUG - 5E6B39D16AFCC2F5B29739A80519B1D0:/ScriptProV1 : CTICommand.execute: callinfo from Manager is error:java.lang.Exception: Hold.doHold:The platform extension no longer has connections to this call - 12424; it could be that the extension has been disconnected from this call
29/09/2014 15:33:09:978 INFO - 5E6B39D16AFCC2F5B29739A80519B1D0:/ScriptProV1 : Capturing exception [com.avaya.sce.runtimecommon.SCERuntimeException]. Message [java.lang.Exception: Hold.doHold:The platform extension no longer has connections to this call - 12424; it could be that the extension has been disconnected from this call]
29/09/2014 15:33:09:979 DEBUG - 5E6B39D16AFCC2F5B29739A80519B1D0:/ScriptProV1 : session id:mppsvr001-2014272203210-19 | ScriptProV1:CBA_CTITransfer | Could not place caller on hold
29/09/2014 15:33:09:981 INFO - 5E6B39D16AFCC2F5B29739A80519B1D0:/ScriptProV1 : Using SCESession 5E6B39D16AFCC2F5B29739A80519B1D0:/ScriptProV1 servlet : hangup