Does your XP account have administrator privileges (control panel > user accounts > you'll see there whether your account is a Computer Administrator)?

Did you try running in compatibility mode for both Win 2000 & NT?

I spoke a little too soon yesterday. I rebooted my machine after I installed the latest Java and ran the crap cleaner and was able to successfully install it. Problem now is when I try to launch LimeWire, I get the same error message. I'm doing all of this logged in as administrator. Pretty Weird