Update line 29 from:
WA_DFP_UploadFiles("WA_UploadResult1", "FileUpload", "0", "", "false", $WA_UploadResult1_Params);
to:
WA_DFP_UploadFiles("WA_UploadResult1", "multiplUploads", "0", "", "false", $WA_UploadResult1_Params);
It looks like you didn't update the code references when you updated the file name. You probably need to delete the form validation from that field, so remove this line:
$InsertQuery->bindColumn("FileUpload", "s", "".((isset($_FILES["FileUpload"]))?$_FILES["FileUpload"]["name"]:"") ."", "WA_DEFAULT");