Here two solutions exist:
Connect this machine to Internet, then click on the right button on the window (Relata a problema...), then web-browser will open and you will be able to report the error to special bug-reporting site named LaunchPad.
Prevent appearance of the future error messages by executing the following commands:
sudo rm -v /var/crash/* sudo sed -i "s/^enabled=1/enabled=0/" /etc/default/apport
and then reboot machine.
The first method is good and useful - you report the error to make Ubuntu MATE better.
The second method is good only for you, it disables bug reporting to prevent user distraction.