I tried again, but still got directed to the Forbidden page.
Also, I just spent the last hour trying to get back on here, but the connection was timing out (which happened the last few times after the 403)... I haven't had this problem on any other site. Only on the occasion. It just seems to happen in that thread.
I do take my laptop to my brother's place a couple times a week, so I know I don't always sign in with the same IP, but I don't think that's the problem.