I have been having this problem today. On the last step, after seeing the Billing Summary, I click the next arrows and it just sits there. In IE, the progress bar gets about half way and then just stops.
I submitted a ticket [JH #AIJ-63883-260] and the support staff were able to create a test account without any trouble.
I tried to create an account on my end several more times but could not.
I gave the tech support department the exact information I was inputting and they created it with no problem.
They said there must be a problem on my end, but I cannot think of what it could be (I've had no issues with my internet connection or computers as fas as I know). I've tried both IE and Firefox, and both a Vista PC and XP PC.
Incidentally, the last account I created was last week - everything worked fine then.
If anyone has any ideas, that would be great.