Unlike people have asked at here and here, I got this error after a brand new installation of Leopard (hackintosh), this problem really driving me crazy a
In my case, I was adding a target to an existing app that had always worked. In my case, I had forgotten to select all the source code, xibs, frameworks, etc. and click their target checkbox. My clue was that the build happened instantaneously, which didn't make any sense. It never built anything. It just failed to install in the simulator. Once I included all the source files, etc., for the new target, then it built and installed fine.