Authorize.net - Missing STATE in address

[TheGiops]

Hi!

Running VM 1.1.3

Active?: Checked   
Payment Method Name:   Credit Card
Code:                   AN
Payment class name :    ps_authorize    
Payment method type:   Use Payment Processor

The Auhorize.net customer service tells me that the transaction isn't good because the STATE is missing in the address.

Anyone knows what is going on?

Thank you!

Piero Giorgi