Errors followed by command "Sudo nautilus"

Solution 1:

You don't need to bother with this things. These are not errors but warnings. It is probably for the reason that, the root user has no session currently, and you are not logged in as root. so ignore these messages.

You can get rid of these kind of messages (if you want) by running gksu nautilus command in the run command window. Pressing alt+f2 will bring up one.

The terminal way

you can open nautilus with root access in terminal without error messages by typing this
sudo -i nautilus &> /dev/null. Here the error messages are redirected to another output device, which is simply null or nothing. See this answer for more