If you remove the user 'testuser' from the file and start the console you should see a page with the hint
"Welcome to AS7, your server is running"
and a description how to add the user.
After adding the user you will get the login dialog box of the browser.
I suppose you get a different error page that shows connection problems.
Could you post how you start the server, what version do you use, and whether you start with a fresh unzipped installation?