@Marvel
You may try with QuEnc as audio converter as well. BTW, to understand better what's the problem, can you copy&paste here the log files of your trials?
About recover mode, here you are a workaround: delete the log file (i.e. test_0.log) and the audio file with error (test_0.ac3) and leave the video file (test_0.m2v). Next time you start the project (test), you will be asked to keep the video file (test_0.m2v). Easy, isnt'n it?
Bye