Strange, i don't have problem with this. Where to start? That is all what you can give to us?
1. Did you run updates?
2. Did you check if msf is connected to data base? (to check this type db_status and you need to get message "postgresql connected to metasploit4" if not in msf console run db_connect -y /opt/backbox/config/database.yml)
3. Then you can open Armitage
And as you can see, you just need to read your error message (
http://www.fastandeasyhacking.com/nomsfrpcd). But before this, check steps I mentioned before.
Etc ...