places where register_globals can be set
I have hostgator account too.
In hostgator and certain other host providers the php.ini that overrides the default values should live in /home/USER/ (i.e. check if /home/USER/php.ini exists, where USER is the username of your hosting account). Make sure that this file has register_globals = Off.

If /home/USER/php.ini is not there then either copy the default (if you have shell access check php.ini location with the command php -i | grep php.ini and then copy this file to /home/USER/php.ini) or ask tech support to help.

More details can be found here on HostGator support site.

Finally, if you are using drush on your host account you might encounter "Register globals detection" issue in which case I would suggest the solution in comment #6, i.e.

cd drush/
ln /home/USER/php.ini php.ini


the resason for this is that drush script (drush/drush) checks for drush/php.ini and if it does not find it there it detects the default php.ini not the /home/USER/php.ini one.