snmpwalk -c public <ip> 1.3.6.1.4.1.9.9.68.1.2.2.1.2
positive
You mean it lists the VLANs? Could you copy a couple of lines so I can verify? But NAV should be able to find the VLAN info in that case. Could you give me the output of the following SQL command?
select oidkey from snmpoid join netboxsnmpoid using (snmpoidid) join netbox using(netboxid) where ip='<ip>';
Replace <ip> with the IP of one of your devices.
-- Kristian