It seems to be working for some and not others. I'm not sure what it could be, so guess we wait on Veks to offer words of wisdom :)
Apparently Google and Apple in their infinite wisdom have adopted a new AJAX standard which causes the entire transaction to terminate because I'm setting some POST headers manually. But it doesn't need to set them at all. I'm not sure why it's broken in any version of Firefox or IE, though. Maybe some other security plugin is doing it.
I'll need to set some time aside one morning and see how stripping it out works when I update the forums.