I would like to have changed this message...
... to something more general like "no input signal present", for example.
I know, this is not a real bug, but might be confusing some user because e.g. on ubuntu systems the device node is created under /dev/dv1394/.
Second reason is that this message also appears when the camcorder is simply turned off.
So, generally there is no need to check permissions on ubuntu, but just to turn on the camcorder ...