Errors with redefinitions after upgrade to XCode 3.2.3

I recently upgraded to Snow Leopard and Xcode 3.2.5 so I could test on my iPod Touch and iPhone and ran into some problems with the project I was working on. First it couldn't find a Base SDK, then my old frameworks weren't hooking up correctly. Finally after setting开发者_运维知识库 the Project Format to Xcode 3.1 compatible (3.2 also worked) and the Base SDK for all configurations to iOS 4.2, then setting my iOS deployment target to iOS 3.0 I was able to get the system to find a Base SDK and attempt a build. That's when the frameworks didn't want to cooperate. 4/6 I'm using displayed in red, so I re routed the path to the iPhone simulator 4.2 platform which worked perfectly. I was able to build my project, no errors or warnings and my app worked fine. I went to work last night thinking I had fixed the problem. This morning I fired up the laptop and went to build my code base and now have 1142 errors all of which have to do with code I haven't written deemed as being redefined. Suggestions? The following is just a small sample of the error list (obviously don't need to see all 1142)

//Frameworks/Foundation.framework/Headers/NSZone.h:48: error: redefinition of 'NSMakeCollectable'

/Frameworks/Foundation.framework/Headers/NSObject.h:65: error: duplicate interface declaration for class 'NSObject'

/Frameworks/Foundation.framework/Headers/NSObject.h:67: error: redefinition of 'struct NSObject'

So I ended up deleting all frameworks from the project and re adding them as existing frameworks, then cleaning all targets and it worked.