Fofer: I'm using the BOOM PSX -> USB Converter adapter. Works great with the GH controller. I bought them about 2 years ago so I don't know if they still make them. These weren't the PSX/N64 ones, just PSX.

Fofer: Add Frets on Fire to the Master Exclude List in Application Enhancer. I've found out for me that it doesn't work well with AE modules like Shapeshifter, Silk, etc.

I'm on a PPC Mac though so YMMV