register_globals on?
Should I turn on register_globals in the php.ini?
No, you should definitely not do this. Besides it being a huge security risk, register_globals also makes you lazy.
Make sure register_globals are turned off, and if you cannot turn them off because you do not have access to the php.ini, you can try to put the following in a .htaccess file (if you are able to use .htaccess): php_flag register_globals off.
If you still cannot turn off register_globals, you'll either have to live with them, or try asking your webhost to turn them off.