i just converted an .avi DivX file to mpg, and when i played it the second half of the movie has only audio, no video

here are my computer specs:

PII 300MHz
256MB RAM
Windows XP Pro
Voodoo2 12MB
VirtualDub 1.4.9 (Convert Audio to WAV)
TMPGEnc 2.54.37.135 (Combine Audio with Video & make MPG)
NTSCFilm template (23.97 fps)

i really dont know what is wrong i did everything that i normally do to convert my avi's into vcd format, someone let me know how to fix this

any help appreciated, thanks