Gary Heston wrote:

  Re-entering it just gets me the log in request again. I don't see
a FAQ page or anything for resolving problems, so can anyone tell
me a) why I have to "log in" just to activate an account, and
b) why it's in this endless loop?

a) Because Berkeley says so

b) Are you accepting cookies and bypassing any proxy on your machine?  I frequently get loops like that from sites that require cookies or java or javascript.  Bypassing my proxy temporarily works for those sites.  I cannot recall if I had to do that when activating Seti.