Xcode Error Log: The selected destination is not valid for this action

Recently, I downloaded a sample project from the mighty internet. It was from Apple so it provides the .xcodeproj file. So I conveniently opened the project and press run to check what the code is all about. And I got this error: The selected destination is not valid for this action. 

After googling around, the problem is simple enough: Some properties are f* up when transfered from older Xcode to newer Xcode. What I did to fix this is to go to the project settings, and find Base SDK. It was set to ppc_something, and Xcode 4 does not support those SDK. You have to convert it to the newest one. I set it to 10.6 to be safe in the future. 

Probably its just because I downloaded a very old code. But its from Apple official website, so they should give a warning or s**t!