OK, so it must be that the rdf class include for some reason stops the script, it really shouldn't be able to though, since it in itself does absolutely nothing.
Try adding this:
<br />echo "Going to load rdf class now...<br />";<br />
Above this:
<br />// Include the RDF class<br />require_once("rdf.class.php");<br /><br />echo "rdf class loaded<br />";<br />
Just to make sure it is actually when loading the class and not for some other reason it dies...