I have been seeing the following error message a lot whenever I build something using the simulator:

dyld: Symbol not found: _objc_collect_if_needed
  Referenced from: /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator3.1.sdk/System/Library/Frameworks/Foundation.framework/Foundation
  Expected in: /usr/lib/libobjc.A.dylib
 in /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator3.1.sdk/System/Library/Frameworks/Foundation.framework/Foundation

I am running XCode 3.2.2 on OS X 10.6.3, and have reinstalled the SDK twice with no avail. This error makes running any code on the simulator something of a Russian Roulette, but with 5 out of 6 chambers loaded.

I have checked the files mentioned in the error message, and they all checkout as being present.

This sometimes go away if I restart XCode. Other times I have to logout, or even restart. And sometimes nothing works.

I have googled this, even tried apple's developer forums. Other than a reference to this in the MonoTouch list, this bug appears to be completely unknown otherwise. Anything help would be greatly appreciated - this is a real PITA.

Cheers, Steve