iphone - Xcode 3.2.3 refusing to run simulator 3.1.3

I have a project build to work with iPhone 3* and 4. Base SDK is set to 4. Target OS is set to 3开发者_运维知识库. I have an iPhone 3GS with 3.1.3.

Xcode 3.2.3 refuses to install the app on this iPhone. It refuses also to run the simulator.

WHen I try to debug on the device I get "Failed to upload". When I try to debug on the simulator I get a message telling me that "simulator could not find the sdk"...

Any clues?

thanks

I have resolved partially the issue changing the compiler from GCC 4.2 to LLVM GCC 4.2.

Don't ask me why, but now I can install the application on my 3GS running 3.1.3.

The question is: why GCC 4.2 is not working.

At least the solution for this question is this.

To expand on Jason Coco's answer: If you go to the Project Info screen and click Build, you can choose what Base SDK to use (4.0) and then scroll down to iPhone OS Deployment Target version and set it to 3.1.3 or whatever. However, you also have to go to the Targets section under Groups & Files (red bullseye) select your target and get the Info build page, and set your iPhone OS Deployment Target there too.

Did you do that also? (from the link posted)