When you choose the mcrypt library to be added to the apache/php install from within cpanel/whm it will actually install them in another path and not update the php.ini file.
This means that the CBC.php file will never be found unless:
1. cpanel changes the way mcrypt is intalled
2. you add the following line to the path variable in php.ini
Any comments from the cpanel team?
cPanel.net Support Ticket Number: