I'm sorry you are having trouble with this part of the support process. Unfortunately it is one of the limitations in teh support model we have been using. The good enws is we have a new support system that will combine with forums, extending the available support and making it easier to access the tutorials, downloads, and other important details withotu having to go through a second verification for the transaction. We are testing this and hope to have it out in the near future.
I know this doesn't resolve your specific issue, but I want you to know that this is something we are working to making much more user friendly.
In the interim, here are a couple FAQs on this issue.
http://www.studiopress.com/support/faq.php
If that doesn't help you get your forum account setup, please use the contact form to request help with this issue.
http://www.studiopress.com/contact
If you have been through this already and used the contact form, please leave your email address used in the contact form here so I can find it and try to get someone able to help with this part directly. There is a slight backlog in the contact form, so it might be good for you to leave the email address either way if you need to go to the contact form. A couple of the people that would normally be on top of the request are on holiday this weekend.