Thank you so much for that information.
I have checked the config file and that all seems to be fine.
This is the actual code it is referring to, which makes me think its something to do with some code somewhere referencing the 'old' datebase with a different cpanel username at its front.
"//CHECK FUNCTION
function check_db_existance($table) {
global $wpdb;
$tables = mysql_list_tables(DB_NAME);
while (list ($temp) = mysql_fetch_array ($tables)) {
if ($temp == $table) {
return TRUE;
}
}
return FALSE;
}