I recently encountered this same error message, and was confused as my code was executing properly. I was able to trace it through searching the *.LST file for "WARNING", and found it in a LOOKUP command. My byte length "index" ranged only 1 - 12, and my "variable" was defined as VAR WORD. But 3 of my constant values exceeded 255. Oops! All it took was changing to the LOOKUP2 command in order to handle word length constants. My code was executing properly because my index value was not reaching any of the word length constants. It would eventually have crashed.