Psp Video 9 Help

[saratp]

Okay, I downloaded Psp video converter 9 Version 4.07.
I do the steps like it says to do.

(After conversion)
Plug your psp in, Open up your folder, Drag and drop/copy your file into the video folder
and you should be done.

I convert it to a MPEG-4 and when I go to play it my psp says "This video cannot be played."
I'm not sure what the problem is though, I used to have the program on my computer
so I have older videos on my psp that I did a while back.

So tell me, what am I doing wrong?