It is a new PSP, so maybe something has to be activated? I have converted 3 movies to the supposed format my PSP can play, but, of course, I go to see if it worked and, "unsupported data". I am boggled! It could also be the program I am using to convert the files; Pazera Free PSP Video Converter from downloads.com. It has a language selection for it, the other language other then english is polski, maybe international issues (don't know exactly what it's called) like DVD from Europe can't play in a DVD player in Canada. Again, boggled.

I suggest using a different program:

Converting your video files to play on the Sony PSP

The PSP won't play mp4's that are too large or have too high of a frame rate. Try using a different converter