I get nothing from the debugging before and I get nothing printed with clean file and your version of rdf.class.php. That tells me that the problem is before this file? It should print your echo line in the rdf file but instead nothing but hang. I put the error_reporting line in index.php and it spits out errors for the pal boxes that load and the page stops when it gets to where the custombox3pal.php box is suppose to load.
Everything has write permission from the server.