If PHP can't find a class it should then call spl_autoload_register can you put a simple echo in there that outputs some static text?
What version of PHP are you using?
Also can you replace the content spl_autoload_register of with:
$file_name = str_replace("GrabzIt\\", '', $class_name) . '.php';
if (strpos($file_name, "GrabzIt") === 0) {
include($file_name);
}
This does not require a file lookup.