Description
On shipping calculator page there is an error at the top:
Notice: Undefined index: user_names in /home/public_html/shipping_calculator.php on line 492
 
Solution
http://www.viart.com/downloads/shipping_calculator-4.2.1.zip
 
Download the file above and extract 'shipping_calculator.php' in the root of your shop replacing existing file. Please do not forget to make a backup copy of the current file in case something goes wrong.

This calculator is not working with my cart. I had to revert to the 4.2 OEM calculator since it was the only one that worked. Now I went back from the 4.2.1 version to the 4.2 OEM, it now works.
 
Ed