Somehow you have fallen into a wormhole and ended up in the Adobe Captivate forums. You need to be asking your question in the Premiere forums.
Grab that OhShucks! handle and hold on tight. I'll move the thread to the correct venue where you may find help.
Glad that Rick got you to the correct spot.
Now, the only thing disabled with the trial is EVERYTHING related to MPEG. You are obviously not working with, or trying to work with, MPEG, as you have mentioned other file formats, and are having the problem with them all.
I'd start by outlining your system's specs., as it seems to be a global problem and not specific to a file format/CODEC. That might help someone spot a problem.
Good job Rick. Hopefully someone will see the issue and can help. When I saw "trial," I jumped to the conclusion that the issue would be with MPEG files, which are not supported in the trial in any way. That does not seem to be the case here.