Generate SSH Host keys -
If you're getting this error when trying to start sshd:

Could not load host key: /etc/ssh/ssh_host_key
Could not load host key: /etc/ssh/ssh_host_dsa_key
Disabling protocol version 1. Could not load host key
Disabling protocol version 2. Could not load host key

Re-generate your host key with this command:

ssh-keygen -t dsa -f /etc/ssh/ssh_host_dsa_key

That should get you sorted, make sure you tell everyone who accesses the server with secure shell that the host key has changed, because they'll get warnings about it and may think that the server's been compromised.

-Jonesy