I have trial version, just started to look at your tool.
We made suggested changes to the Cisco router 3800 Version 12.4.
I can see new sensor with gray color and status unknown. As a result no data is collected. Since we just started I have 10 sensors enabled. Can you tell us what did we do wrong with config? I can read bandwidth data from interfaces after we added this line to the router snmp-server community our-key RO
Changes we made for NetFlow on Cisco router:
rr-bdr-1.nyc(config)#int gi0/0 rr-bdr-1.nyc(config-if)#ip route-cache flow rr-bdr-1.nyc(config)#int gi0/1 rr-bdr-1.nyc(config-if)#ip route-cache flow rr-bdr-1.nyc(config-if)#ip flow-export version 5 rr-bdr-1.nyc(config)#ip flow-cache timeout active 5 rr-bdr-1.nyc(config)#ip flow-cache timeout inactive 10 ip flow-export destination 10.128.16.50 999 --- this is computer where prtg is running