I received this error today after inputing Apple's "Your third iOS Program", SimpleTextEditor.xcodeproj.
After struggling thru the error message, and replacing a lot of the code with cut/pastes from Apple, I went to their forum, and found the problem.
I mistyped this statement - #import "STESimpleTextDocument.m" as an import for the DetailViewController header file. It should be .h
Forums rock!
