Steam released a demo for Champions Online today, and as soon as I saw it I downloaded it. I do all the registering crap, and when I try to login on the main splash screen, it says "account error, please contact billing support." I made two different accounts, and I still had the problem. I verified my account and everything.
 
Anyway, I don't know what else to try. Anyone else having problems with the demo?

Same problem here.  I opened a ticket on the dashboard but have yet to receive a response.

I'll give this a bump. Anyone?

Try their boards, someone will have made a topic I'm sure.