New to nav system

Hello, I just installed nav system from source, so I have 4.0b5 up and running. I tried so far only few Cisco boxes of these two types - Catalyst 6504 - Catalyst 4506 Even on these I'm unable to obtain software version, modules etc. It shows serial numbers and ports (but not switch ports or router ports) I tried to find out, how to troubhleshoot the proces, but nothing was usefull. Can you please advise me, what can I do to make it work? brgds Mat