You may not have to wait for support to fix this one for you. Log ito the panel > Domains > Manage Domains. Click to edit the domain or sub-domain you're getting the error from. Now click to submit (even though you didn't make any changes).
This forces Apache's configuration file, httpd.conf to be re-written, hopefully fixing your problem. It takes a bit, maybe up to a few hours for it to actually rewrite it, but hopefully that will fix your problem.
If you've already put in a support ticket, why not go ahead and try this method, and if it works you can then remove the ticket.