I'M STILL ON 3, SO NO PROBLEMS HERE.
In all seriousnes, here's what I have done in the past with the 2005 edition. I eneterd the autorization code while not hooked to our server and/or internet. Than when the daily verify messes up, I unhook the internet cable and start Autocad. No internet service, it links to the internal authorization code. Ain't that silly??