[Brian M.]

Make sure that you have the "Include Path" under Project-->Build Options...-->Project equal to "C:\mcc18\h". The default location is "C:\mcc18\" but if you installed the C complier somewhere else, change it to point to that location. While you're in the dialog box make sure the "Library Path" equals "C:\mcc18\lib" (or the equivalent if you installed in a different location).