clamav(antivirus) scan thro php

[mjm7867]

i am running Centos 4.4, apache 2.0.1, PHP 5

where $tmp_file = $FILES['uploaded']['tmp_name'];

i am uploading a file and while it is in upload_tmp_dir i am scanning it with clamscan(command line antivirus),
but when i run it i get this error in error_log:
so the code is like this :

$tmp_file = $FILES['uploaded']['tmp_name'];
$result = system("clamscan $tmp_file");

ERROR: Can't access file stuff.txt
stuff.txt: Permission denied.

need help please i m stuck on this for the longest time.
Thanks in advancee!!!