Are any of the interfaces showing a green checkbox in the "Sending NetFlow" column? You can only start a capture for those interfaces that are sending NetFlow data.
when i started the app this morning, i saw the device 2 times in the netflow analyzer. one of them had the green check boxes, the other one didn't (removed it)... so i could start the capture!
again the magic of a reboot and a good night sleep in full effect? ;-)
thanks for the reply nonetheless!