[Kevitt]

No, I'm thinking that line is simply where a database call exists. I think you need to do what the error specifically states.

But... I think for mysqladmin flush-hosts you need to at least be able to SSH or telnet into the server. I think you'd probably be best off giving your hosting support dudes a call

EDIT: I was just thinking that my answer wasn't very good. Sorry... been a damn long day.

FLUSH-HOSTS clears the hosts cache tables. I've only seen the need for this once, when the mysql server had an IP address change and the tables needed to be refreshed. I know that's still not much help, but I just felt a bit more of an explaination was in order.