uploads work sometimes

Hi, I have a form: <input type=file name=pdfFile> And the code that processes the form: if ($_FILES['pdfFile']['name'] == "") { print "You must select a file to upload"; } else { // code to add data to db } This works on my server at home (when I select a file to upload, it sees the filename in $_FILES['pdfFile']['name'], but on a server at work, it's blank so I see the error "You must select a file to upload". Any ideas on why this might happen? Is there anything in php.ini that could be wrong (it works here at home when register_globals is set to on or off)? Thanks everyone, Tyler