Monday 8/1/2011 2:31:53 PM
I did a check of the (obsolete) dev blog of gpsp http://gpsp-dev.blogspot.com/
, especially the most recent entry, i think i got what's going on.
It seems the issue is that some gameboy advance games aren't supported by gpsp because they use a specific function ( which can be only be fixed with some hacks, like Exophase said, but it doesn't fix the whole issue.
I guess it's better when someone should look to the code of VisualBoyAdvance and copy some usuable code to gpsp for fixing it.