Debian server - Apache2 configuration fix

I need help to fix a server. After installing php-apc all websites are down. 500 - Internal error We have a linux RPS server - Debian Lenny I have installed the APC library which has broken IspCP Omega. I have removed APC but still not working. I have reinstalled IspCP and now I have a 404 not found for IspCP admin and all websites hosted on this server. I need someone with the skills to find the problem and fix it as soon as possible. No need to install APC, just fix the websites and IspCP