Um, which of Pete's plugins? If you're using any ATI Radeon, you should use Pete's D3D plugin. The latest version is 1.62. You can also go and download new drivers if they're available. I'll check to see if there is a special fix for GT2. Edit: There are no special fixs for GT2.
I remember somewhere reading that OpenGL doesn't work very well with Radeons. So, Pete's D3D will work better. Make sure you use the D3d plugin, not the D3D DX6 one. And check for updated drivers. Do you have Direct X 8.1? If not, download it.