I have a real stumper!!

I run php4.1.2 on a windows xp professional system compiled with apache. when i call config.php it returns an erorr. "can't find include file in c:/php/pear" now i've played around and figured out that in my config.php file i include another file called mysql.ini i include it like this ... include"includes/mysql.ini"; thats when it gives the error. buy if i say ... include"./includes/mysql.ini"; the error doesn't show and the script runs perfectly. there is an error in my php.ini file somewhere i can't seem to find it. any suggestions ?? Please help