subdomain indexing problems

Googlebot is having problems indexing my subdomain

[MrBlack]

I have a forum installed on a subdomain, which is accessed by the url [forum.mydomain.com...]

Googlebot has however indexed it as [mydomain.com...] and now the links that appear in G's index do not work.

Should I have used a redirect or something?

Thanks for looking

[shogun_ro]

A 301 redirect in .htaccess is ok.