Also make sure the email account you used on your forum signup is the same email used for your dreamhost account. Likewise make sure you are using the email account you log into dreamhost when filling out the form.
Dreamhost seems to ignore anything they think is fraud. If your contacting from one email address and it's not listed on your account, even if you reference the listed one they may just assume it's someone trying to take over your account.
The security requirements to regain access to an account are very tight, if they weren't it would be the weakest link in two-factor authentication.