I am using a Linux system to try and do some video conversions from WMV8 to AVI

I am using the following command

Code:
ffmpeg -i "input.wmv" -ss 0:0:0 -t 0:5:00 -b 1300k -f avi -vcodec mpeg4 -vtag XviD -acodec libmp3lame -ab 128k "output.avi"
The conversion completes fine, video playback and audio are fine, on my PC's.

However, when i try and watch the media on my TViX Box, I get no Audio, even though the unit recognises the audio stream.

I have compiled ffmpeg from SVN source, and also the lamemp3 too.

Any ideas?