How to solve :
Warning: session_start() [function.session-start]: The session id is too long or contains illegal characters, valid characters are a-z, A-
There is a bug report for this problem (https://bugs.php.net/bug.php?id=68063)
You can check the success of your session_start and generate the id if needed:
$ok = @session_start(); if(!$ok){ session_regenerate_id(true); // replace the Session ID session_start(); }