Now I get error messages making me quit the application all together,
You are posting in the PR forum, not in the AE forum.
Second, the trial does not support anything MPEG. Could that be the cause of your problem?
Well I managed to get two MPEG4 videos from phone before, but it wont let me choose from a list of files because the message prevents me anyway
Exactlyy where are those files located and what files are they? Your description is too vague. If they are from a phone, they could be blocked by the phones sync software or your system#s security tools are holding them hostage because the register as unknown file types....