should move this to Digital Video...
anyway.
If honestly someone has the final product (a DVD) and is asking you to go a bunch of steps:
rip DVD
re-encode the .VOB file into something editable with Quicktime/FCP
edit with program to remove frames
and then, I assume put it back onto DVD, its really a run around that should have been done at the step before encoding the video for DVD.
but anyway, I am not 100% sure what is out there to edit and/or convert .VOB, but since it is basically a container for MPEG2 video, you dont want to re-encode it into anything else. Youll lose quality.
do a little searchin for .VOB editing on OSX or converting.
what is the end result you are looking for? i.e. the final output ?