problems with opendir()

hmm i seem to be having a problem with opendir(). perhaps one of you could shed some light on the subject. here is the line of code (practically right out of the documentation) if ($handle = opendir('$_SERVER[DOCUMENT_ROOT]/files/$dir')) { blah blah blah; } since that gives it the absolute path to the dir. it should work. but instead i get: Warning: OpenDir: No such file or directory (errno 2) in /blah/blah/blah/submit.php on line 445 now i did check to make sure that the directories that it tries to access are available permissions wise. Is there anything else I should be looking for that would cause this? thanks , Nate.