I would advise checking for .htaccess or local php.ini files in your installation directory which are implementing PHP 5.6. A server can run multiple versions of PHP and often there are files like this present setting specific directories to other versions.
Regarding the original issue, this is a server problem (as Marc mentioned). You mentioned GoDaddy was no help, was that in relation to the PHP version issue or this? If the latter, I would suggest going back to them and asking them to re-investigate. If you do have mod_security enabled, have them temporarily disable to test.