This error means that the client has lost its connection to the X server. The "0.0" represents the display device, which is usually the console. This message can appear when a user is running an X application on a remote system with the DISPLAY set back to the original system and the remote system's X server disappears, perhaps because someone exited X windows or rebooted the machine. It sometimes appears locally when a user exits the window system. Data loss is possible if applications were killed before saving files.
Try to run the application again in a few minutes after the system has rebooted and the window system is running.