Subdomain question – The PeerBoard Community

The PeerBoard Community Subdomain question

Hi,

I use the WordPress plugin to use PeerBoard and it worked fine on mydomain.com/community_name. But when I set up to go on a subdomain instead, like community_name.mydomain.com and set the DNS records, after I've got a 404 page when I check the subdomain.

These are my settings:

This is the message on my dashboard:

This is the subdomain:

What should I do?

Thanks,

Tibor