My issues with Kismet on my N800 is it often just stops scanning for networks. You can tell this when the timer stops.

My other issue is it frequently corrupts and destroys all data on the memory card it puts it's log files on. This seems to happen often when it stops scanning, but I haven't done a lot of testing as I am not a developer and I don't like my memory card being corrupted.

Kismet is an awesome program tough and I hope it gets sorted out soon.