I have had the same issue with dumbass Divx framerates...
If it is very close to a known rate (i.e. 23.97), then you can use
AssumeFPS
I don't remember the syntax off hand but it is easily found on the Avisynth site. That will trick TOK into seeing the right framerate.
However, you will have to take a couple of steps to encode properly. Make sure to save the audio as an uncompressed WAV file (VirtualDub). Then open the source in VCirtualDub again and select direct stream copy for the video. Select WAV audio and point to the WAV file you created. Then set the video (under FrameRate) change so video and audio durations match.
You may still get some sync issues but this will be the closes to perfect you can get.
I have found the dumb framerate usually means that there will be several DIFFERENT audio sync issues in the file. The voice will be early for a bit then it will be late.
What do you expect. If someone thinks Divx is better than KVCD then they are probablly not able to make decent Divx files either?
Grantman