Maybe somebody has the same problem as me.

My problem:
I have Priiloader installed and USBLoader GX.
I installed the Forwarder.dol in Priiloader and it worked perfectly except that it didn't play all my games in the forwarder.
It did do that in the normal USBLoader GX.

Solution (with little IRC help from Anthony and sour):
Just take the normal dol out of the package that you installed USBLoader GX with and install it in Priiloader.

This will have the same effect as the forwarder.dol but it will boot the normal loader.

Hope this helps anyone.

Grtz Perz0n