Video Conversion Clarification

I've been looking through the forum and been trying to find out a few solutions to the problems I'm having with my player or possibly the software that I am using to convert my .avi files but the solutions I'm finding seem either to short or confusing. Hopefully someone here can clarify it for me a bit more better.

1) I've been converting .avi files approx 700mb with Video Converter (the software that comes with the player) and somehow the converted file doesn't load on my player. The converted file is approx 380mb, is it because the file size is too big for the player to handle? I'm using default settings on Video Converter.

EDIT: I've been using VitualDub and the 380mb file seems to work therefore I believe file sizes is not much of an issue.

2) I've been trying to use VirtualDub-Mpeg2 to convert the .avi files (followed the tutorial found on this forum) but when I select the .avi file it comes up with Variable Bitrate error, is this normal? Or is there something I must do before using VirtualDub?

EDIT: Small files converted has no sync problems only on films, is there a way to mend this problem? Or do you have to convert the film twice as mentioned somewhere in the forum?

All my Bleach/Naruto anime works perfectly with Video Converter.

Thanks for any help given.