I have two questions : 1. When compiling my project include files in the c51\INC directory can't be located. there is an error ("can't open file 'stdio . h" …..) but if I write the #include with the full path #include "c:\c51\inc\stdio.h" instead of #include <stdio.h> the files are located. My autoexec.bat file is : Set path = c:\c51\bin Set c51lib = c:\c51\lib Set c51inc = c:\c51\inc How do we specify include files that don't reside in the \C51\INC directory? 2. Another error that I've got is: ***FATAL ERROR 210: I/O ERROR ON INPUT FILE: EXCEPTION 0021H: PATH OR FILE NOT FOUND FILE: LIB\C51L.LIB I've checked and the c51l.lib file is in the lib directory What is the reason for this fatal error? Thanks Rafi