The admin access to our demo site was disabled earlier this year due to some security reasons we haven't addressed yet. When you open up the admin area to Joomla to 'anyone', they can (and will) do bad things. We're working to restore admin access, but we don't have a timeline on when that would be available.
You should be able to test and play with all the features on the front-end though. If you have any specific issues with your site, or the demo, just let us know. I saw you have another forum post, and I'll be addressing that shortly.
Thanks,
Alex