Only root can run xconsole.
Other users get "Couldn't open console" in the xconsole window and no
ppp.txt recommends using xconsole to display daemon messages. It is very
handy for watch the login progress, or lack there of.
Configuration issue - you have to be able to read from the device, and most
likely /dev/console is only readable by root. You can pass alternate
files/devices to xconsole with the -file option.