Often times when you've created a new ruby on rails application, or you've installed an existing one, you'll get this error when you try and use the site.

It can be a confusing error, because your config/database.yml file may clearly indicate a mysql username other than root, as well as a specific password to use. So why is it trying to login as root, and without a password?

Most often this is because you need to restart the mongrel process after you make any changes to database.yml. To do this:

1. Login to Virtualmin
2. Click Services
3. Click Bootup Actions
4. Click the check box beside your mongrel instance
5. Click the Restart Selected button

Hopefully that will do it. If not, here are a couple other things to check:

1. Ensure that your mongrel process is configured to run your rails application in the correct mode, whether that be development or production mode.
2. You might want to check that there aren't any tabs in your database.yml file
3. Ensure there aren't any spaces prior to the development: or production: lines in your database.yml file