It IS a plugin problem, but I was just saying, not only has Mupen64's core fixed core game issues that no other emulator has, but it comes with an OpenGL plugin that may initialize properly but it's also relatively difficult to install to the other emulators, thanks to Glide3x.dll, meaning, he may not understand the instructions for installing the plugin.
I'm not saying, use Mupen64 because it's better; I'm saying, use Mupen64 because it comes with a plugin that, for your system, may work better, and while I'm at it, I kind of seen better overall results from its core. If Glide64 didn't come with Mupen64, I would've attempted to tell him how to install it to Project64 instead, but my opinion was off-topic.