php-4.2.3 + Apache

Hi everybody I'm tring to reinstall php ad apache and get a error, this is the problem: I had a a totally functional server with PHP 4.2.3 + Apache 1.3.23 (RPM package for RH 7.3) in this all were all rigth but i try to upgrade Apache to avoid the potentialy security bugs that were reported in past weeks, i download Apache 2.0.40 and compile fine, obiusly i recompile PHP too and apparently all work without problems, but when check my page (this a PHPNuke portal) found a big problem, ALWAYS the function file_exists return false and some MySQL querys (specialy INSERTs and UPDATEs) cause problems. I think this can be a problem with Apache 2 because PHP support for this is experimental. There are any form to solve this? I'm the only people who have this problem? PLEASE HELP ME.