I'm getting the same error:
Could not establish database connection. Please check the username, password and hostname in the config file, and if necessary set up the appropriate MySQL user and privileges.
and I'm not sure what to do...
Edit: Okay, so I managed to get it working. I set the permission of the config file to 777 and now it works fine. New question though: do I have to leave the permission as 777? If not, what can I change it to, so it is safer?