iOS Xcode 4.X : Build Fail "My 64-bit Mac"

This error arose when I began working on a project that a co-worker of mine started. The project was on the iPad using iOS but xcode key yabbering on about how it couldn't build for 64bit desktop. Painful and maddening. Stackoverflow.com showed that this problem happens a lot for several reasons (subversion, files touched outside of xcode, crashes, etc ), but none of the presented solutions were helpful. All except for one.

To resolve this for my iOS project, I went to the project target settings ( the picture of the ruler and brush ), to the"Summary" tab, and changed the "Deployment Target" to 5.0. It was set to something like 5.1, but it needed to be something that my machine had. I imagine that the "My 64-bit Mac" crud is a default that Xcode goes to when all else fails.