Acceptable File Type Uploads

I am using a form to upload pdf files. With no validation it works. If I try the validation it fails.

This is the code:

<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
$WAFV_Redirect = "filetype.php";
$_SESSION['WAVT_pdfmenusInsert_199_Errors'] = "";
if ($WAFV_Redirect == "") {
$WAFV_Redirect = $_SERVER["PHP_SELF"];
}
$WAFV_Errors = "";
$WAFV_Errors .= WAValidateFE($WA_DFP_UploadStatus["WA_UploadResult1"]["serverFileName"] . "",".pdf",true,1);

if ($WAFV_Errors != "") {
PostResult($WAFV_Redirect,$WAFV_Errors,"pdfmenusInsert_199");
}
}
?>


I also tried it using the file extension rather than the serverFileName but that didnt work either. Help?