this line:
$WAFV_Errors .= WAValidateRQ(((isset($_FILES["pdfUpload"]))?$_FILES["pdfUpload"]["name"]:"") . "",".pdf",false,2);
should be:
$WAFV_Errors .= WAValidateRQ(((isset($_FILES["pdfUpload"]))?$_FILES["pdfUpload"]["name"]:"") . "",false,2);
one thing confuses me in your post though; in the validation code, you are validating a file field named pdfUpload, but the file field on your page:
<input type="file" name="pdfFile" id="pdfFile" />
is named pdfFile