parse error inside comment????

Hi Gurus - any suggestions here would be welcome, I'm baffled. I have a file that does this: <? require("function_definitions.php"); //some more stuff here, calling functions, etc. ?> but when I call this file, it gives me a parse error in function_definitions.php. No biggie, so I start trying to figure out what paren, quote, etc. I've forgotton, and I cannot. The line that PHP is choking on is for a function that I'm not using in the above page, so I comment it out, thinking to go back and rewrite it later when I need it, and the parse error is still showing up on the same line!!!! To summarize, a parse error is showing up on a file being 'required', even if the lines in question are commented out. thanks in advance for ANY pointers. cheers! jaxon