Louis stated there was a STACK Underflow flag set in the PCON Register. I looked over his/her posted code and the only place I could find where a CALL/RETURN mis-match could occur was in the posted line of code. By specifying a "GOTO" there, the Stack would not be modified with a RETURN PC Address. I suggested a test to eliminate the possibility of the STACK Underflow condition being caused by that line of code.