Add some more RAM and buy another Video card
Basically your video card does not support some of the functions that the emulator is asking for ( specifically Glide or OpenGL). And since your system is kinda old, if you add some more ram it could possibly make it run more efficient. As for the video card, a 64mb video card ought to do the trick, but I recommend at least a 128 mb card for any emulation of P64. It�s probably AGP but check to make sure!
Just smile and nod, thats the secret to a happy relationship.