Do you have any other application accessing the DVB Device? For example vdr or mythtv-backend in the background?
$ sudo /etc/init.d/vdr stop
$ sudo /etc/init.d/mythtv-backend stop
$ ps fax | grep -i vdr
$ ps fax | grep -i myth
if one of them is running stop them before using kaffeine or mplayer
Are you using the 091009 drivers?
http://support.sundtek.de/index.php/topic,133.0.htmlHow about the signal strength? (you can open the channel scan tab in kaffeine again and it will show up the signal strength for the currently tuned channel)
We received a similar report from another user, claiming that when VDR was running in the background the video stops with Kaffeine. But this has been the nature of VDR and is out of our scope. That for it has to be stopped or the device has to be plugged in after VDR got loaded.
You might also contact our technical skype support chat "Sundtek"
Especially Ubuntu has been tested for weeks(!) on Netbooks now