d2v files are pretty tempermental.
If you let them sit for too long...they don't like to work
if you move them, they don't like to work.
I'd suggest trying 2 things:
1: remake the d2v files
2: use DGindex and DGdecode
instead of dvd2avi and mpeg2dec3.
also, what processor do you have? IIRC, only Pentium4 (Athlon 64) or later processors can utilize cpu values greater than 3