Brief.
We have fixed admin_shipping_module.php after release 3.1 has been issued.
 
Description.
There was a problem with data integrity while deleting Shipping module. Not all data has been deleted, so the database could contain garbage after such operation.
 
Solution.
Please download updated version of the file from here
http://www.viart.com/downloads/admin_shipping_module-3.1.zip
Then extract file admin_shipping_module.php into the folder 'admin' of your shop replacing existing one.