Solve this with:
# chmod o-rwx /var/lib/redis
# chmod o-rwx /var/lib/mongo
If you are the only user with access to the server it's not a big problem. However, it's better to make it inaccessible by other users just in case a cracker get access with non-root user account.
You'd need to modify the theme:
I attempted this last week. It's easier to redirect them. So category.forum.com redirects to forum.com/category/2
I pasted my configuration in another topic. Feel free to look through my topics from the last 2 weeks for one about subdomains