We are running Autocad 2004 and purchased the upgrade to 2005 and joined the subscription program before 2006 came out so we wouldn't have to pay for being 2 steps behind. The 2005 packages came and a couple weeks later a 2006 disk came. The number matches the subscription, but I can't activate. I get a Registration activation error (20). Can't find what that means. Anyone know? Thanks, -S