Sound Bitrate Causing Corrupt Message

[the_Grinch]

Computer Specs:

OS: Ubuntu 8.10
Ram: 1 GB
Processor: AMD 3200+
Hard Drive: 22.6 GB (10000rpm)

The issue I am running into is with my .mkv files. Most have been playing, but some do not. I've found that with some if I changed the Sound Bitrate setting to 256 they will play. But other not matter what I change it too, one of two things will happen: a) I just get the file is Corrupt message or b) the video will play with no sound (which alerts me that the bitrate is too low). Only message I get from the tracers is that it is transcoding, no errors or the like. Any ideas? Other then that great software that is very easy to use!