Hi Chris
If the movie file has an extension type “.avi”, then some users have reported success with problem avi’s using a (freeware) app Virtual Dub here:
http://www.virtualdub.org/index
Open the avi in Virtual Dub and then save it as an avi and it may then work in Registax.
Oh, and make sure you do not capture the audio stream. Also, keep the file size below 1 Gig.
Cheers
Dennis