Do you disable any PHP functions on your Linux hosting accounts?
To change the status of a function, you can use custom initialization (
php5.ini) files. For more information, see Can I add a PHP initialization file to my hosting account?
What do I do when I receive a PHP header error message?
Viewing or Changing Your PHP Language Version
Do you run PHP in safe mode on your Linux hosting servers?
PHP Upload Limits on Shared Hosting
Do you support fsockopen?
Finding Your Account's PHP Version Using Phpinfo