I've saw a report in the bug tracker about the postgres test server being down. I don't know the root cause (yet).
But here is how to fix it so you can move on:
1. Go to http://test.openacs.org
2. Click "all sites on this machine"
3. on the dotlrn-21 line, click "more info"
4. Scroll down and click "Rebuild this server now"
This will reinstall and you can then get in.
