Hmm, that's strange. I don't remember having any trouble getting onto the forum when I joined GWAPA. Have you tried contacting one of the board? (go to GWAPA.org, then click on the link About GWAPA. There should be contact info for at least one of the board members)
By the way, in case you didn't know, there's a meeting this Saturday. Topic will be "Lighting the Planted Aquarium." Should be very informative, and the mini-auction is always a lot of fun! Info and directions are on the site.