Update your GPU god damnit.. OpenGL 1.75 is out. If that still doesn't work and you just can't get pec to work, just fight and rest by a town with the fps limit off, using a petes soft gpu temporarily (or another which is light). I got fps of 500, and got through some boring levelling up damn quickly.
I think there's also another cheat plugin or something similar for psx emus. Not sure though. Might be confused with another console emu
Also, you can try using another emu, like VGS to run that bit temporarily (uses a different method of code application i think), or you could get the codes from another source. Try codejunkies, gameshark, or gscentral. Gscentral has craploads of FF7 codes, and was the only one with affection modifiers, and loads of funky codes, if you don't really want to cheat, but get more out of the game (like me, although i usually cheat like hell)