This bug has been driving me nuts since I started using Xcode (4.6.3). Whenever I try to link a Storyboard item to my code, I get the error:
Could not
For me, the view I had specified a custom class for was failing to be compiled by interface builder. It was marked @IBDesignable.
@IBDesignable
Removing @IBDesignable, and then adding my outlets, and then marking it as @IBDesignable resolved the issue in my case.