With Nikon D7000 video files, I get a "can't render" message in the thumbnails, although the video will play in the large preview window. Also, as I click on to view and play these videos, I get additional, bouncing PM icons in the Mac dock. After having to force quit PM 5 Beta, I have to force quit each of these additional bouncing icons. I have no issues with these files in Final Cut Pro X, Premiere Pro CS6, or Phase One's Media Pro.
Mac 10.7.4