Thanks for your help. =]
I finally got it working. I don't know exactly what the problem was, but i tried differents of combination of configurations and one of them worked.
It is this way now:

Video

128x128
High
High
mode0

Misc

Overwrite file NOT CHECKED
Try other coded CHECKED

It's a 1.5 display. The player is a Nano iPod like.
All my videos gnow work on it, but the two samples that i got here still don't.
I dried to do what you said, of getting everything out of it, but still didn't work, maybe my player requires a specific configuration.
I can upload the video and also a picture of the MPX Player if you still want it.

Thanks again for your help.

Raphael