Back again!
I ran without logging in in Gnome at the console:#pw groupmod operator -m jv and this time sure enough jv appeared in the /etc/group file besides operator. But still no luck with scanner.
#echo "test" > /dev/ugen0 tells me: Operation not supported by device
#cat /dev/ugen0 tells me: No such file or directory
If that is not confusing
I will survive!
borgibo