ACM stands for Audio Compression Manager so we already know the problem is with the audio in the source file! It could be a codec problem, you should get gspot to check the file if its an avi. Also, you can try using VirtualDUB to decompres the audio on an avi file, this has fixed the problem in the past! So open the avi in VirtualDUB and do the following...

1. Click Video - Direct Stream Copy.
2. Click Audio - Full Processing Mode.
3. Click Audio - Compression. Select <No compression (PCM)> and click ok!
4. Click File - Save AVI and try it with TMPGEnc.