This plugin will allow you to display a list of Moodle courses for a specific user of Moodle.
This plugin has been tested and approved for Moodle version 2.4 and WordPress 3.5. I am pretty sure it will work with any version of WordPress 3+.
You have not properly edited the plugin code. You must provide a connection to your Moodle database. This should be a READ ONLY user account.
Most likely your database connection settings are incorrect. Please recheck and verify you can connect using the user and password for MySQL.