Problems with Roundcube Database

Hi Everyone

am new to the forum and new to the centos web panel. i have just started using it. everything was running great for a few days (testing period) then all of a sudden i get this error message when loading roundcube.

DATABASE ERROR: CONNECTION FAILED!

Unable to connect to the database!
Please contact your server-administrator. 

Using the URL - http://host43.co.uk/roundcube/

am a new user to linux aswell, any help would be fantastic.

keep up the good work with CWP,

Thank You