I had this same issue on my last reinstall, and corrected it.
First, as WolfBane said, you must make sure if you set a MySQL password, you update your config.php file.
Other than that, the fix that worked for me for this issue was to stop and start the MySQL service. After that it works fine. Try running the following in Terminal:
[CODE]sudo service mysql stop
sudo service mysql start[/CODE]
If you go to the web interface after this, click next on the database schema update page, does it let you go on? If yes, then see my permanent fix for this solution [URL=‘http://fogproject.org/forum/threads/mysql-problem-what-am-i-doing-wrong.10515/#post-27515’]here[/URL].
Hope this works for you, let us know!