Looks like Dreamhost upgraded our sites to PHP5 on October 4th. Not sure whether we were notified about this or not. Or somebody on our team did it and I wasn't aware.
HTTP_GET_VARS is now _GET in PHP5.
And this was the line I put in the top of my file to debug:
<?php ini_set("error_reporting",E_ERROR | E_WARNING | E_PARSE | E_NOTICE | E_ALL); ?>