If your friend is set up in group "User" only, there is going to be a plethora of these type of errors. Get your friend to run this command with his username instead of '<username>'
cat /etc/group |grep luser
I would recommend joining the groups: disk,lp,wheel,audio,video,uucp,plugdev,scanner
that can be done as root by this command
usermod -aG disk,lp,wheel,audio,video,uucp,plugdev,scanner <username>