<<<The aif file and the m2v files have corresponding filenames. I'm at a loss. Help!>>>
Those are the two Elemental Stream files that when imported into DVD Studio Pro, will produce a movie DVD. The m2v file is a classic MPEG2 compressed video stream and yes, indeed, you can't edit it--or at least not easily or conveniently.
MPEG2 uses temporal compression which means it compresses time. Only every fifteenth or twentieth frame in an MPEG stream is real video, the rest of them are small bookkeeping files and you can't cut them.
I think you need the MPEG2 plug-in for QuickTime Pro to get all the right tools and conversions.
I think DVDxDV will do it, too.
Koz