[Alan Anderson]

The other possibility is that you've copied your code to another directory. Until you do a "Clean" (or a "Build"), something in the MPLAB project information is still pointing to the original files, and it picks up some of the same data twice.

The easiest way to fix this requires a single keystroke. Instead of just pressing F10 to compile, use Control-F10 to do a full build of the project. That will clear up anything still hanging on from the previous directory. Once that's done, F10 alone will be fine -- until the next time you copy your code to another directory.