Thank you for your quick response.
The validation scripts are before the upload scripts. I chose Validation as File Extension. The variable is vendorLogo Extension. When choosing the variable the value is: <?php echo (((isset($_FILES["vendorLogo"]))? preg_replace('/^.*\./', '', $_FILES["vendorLogo"]["name"]) :"")); ?>
It still doesn't work.
I've attached two pics of the screens with the choices I made.