Ah, you're trying to do DVD imports. Well, it depends on what you
want to do. Probably you're going to want to use the entire kickstart
tree from that DVD, so that's as good as a place to leave them as any.
What I normally do in this situation is add a symlink, like
/var/www/cobbler/local_mirror/fc6tree -> /opt/dist/fc6
Correction: the way you invoked the import (using the root:localhost@
syntax), you don't need to do this at all.
Check to make sure content did get copied to /var/www/cobbler/ks_mirror
though ...