When I import .m2v files to the timeline, some of them (only in the video track) are not showing. I tried to open them on other programs, like Windows Media Player, and they won't open too. BUT... when I tried to work with these files in another computer and another version of Encore (mine is the one that comes in the CS6 Master Collection), they seemed to work fine, and I could finish the DVD authoring. What could be the problem?
Sounds like a codec issue - present on one computer, not the other.
In the "bad" computer, Encore is activated, right?
Can you play one of the m2v files from the Encore library? Example, on my pc, C:\Program Files\Adobe\Adobe Encore CS6\Library\Entertainment\NTSC\NTSC_Nightlife.m2v