Guys, My isp has just sent me a reply re this problem, They are familar with UBB (Fame Eh) and say a file was altered today (Trying To Find Out When & What Ip Address)...
I guess it just needs filling in again, but this is a major worry, who did this, can threads do it itself, I am the only one with FTP info....
Should I be worried..???

Dear Customer,
The main file (config.inc.php) which is included within ubb was altered today before you contacted us regarding this issue, the below section is missing the database information, once it is corrected and reuploaded, your site should work correctly.
$config['dbserver']= "";
// Username that has permissions to the database
$config['dbuser'] = "";
// Password for the database
$config['dbpass'] = "";
// Name of the database
$config['dbname'] = "";
I hope this has been of help.