MPLAB...ERROR..Pls help..Thank You

[ocean_blue74]

I have just installed MPLAB IDE V7.40 with a MPLAB C18 Compiler,

but when I build all. there are error messages appeared.

Clean: Deleting intermediary and output files.
Clean: Done.
Executing: "C:\MCC18\bin\mcc18.exe" -p=18F4520 "Test.c" -fo="Test.o" -Ou- -Ot- -Ob- -Op- -Or- -Od- -Opa-
C:\MCC18\My Project\Test.c:1:Error [1027] unable to locate 'p18f4520.h'
C:\MCC18\My Project\Test.c:2:Error [1027] unable to locate 'delays.h'
MPLAB C18 v3.02 (demo)
Copyright 1999-2005 Microchip Technology Inc.
Days remaining until demo becomes feature limited: 60
Halting build on first failure as requested.
BUILD FAILED: Sat Aug 12 15:07:03 2006

Thank You.

I have make sure that Project>Buile Options>Project there is C:\MCC18\lib in the library path. But I do not know why the MPLAB cannot find the header.