I was locked out by Error Code 603 also. I tried every fix I could find in TT Help and from the community, but nothing worked. I finally called. The first tech support's response was basically, "Sorry, dude. The system shows that it's been activated five times. Once it's been installed five time, there's nothing else that can be done. You have to purchase another copy." I firmly requested an escalation to a supervisor. After about 30 minutes, one came on the line, understood my problem immediately, sent me a new activation code, and stayed with me while I checked to make sure it worked.
The moral - don't let the first line of defense intimidate you. There really are people there that know what they are doing and want to help the users. They understand that that is what will keep us returning from year to year.
