If your Butler robot is losing communication in the middle of operation it is likely that it is losing power, and is resetting the program. Try the following basic troubleshooting steps to resolve the issue.
Try to switch the outlet that you are plugged into is not sending a steady current you will lose power to the robot, and the system will reboot.
If you have an additional network style cable, Not an Ethernet cable, you can try swapping that out. In rare cases a bad cable will send an inconsistent signal causing communications to cease.
If these options do not work for you contact your dealer for assistance.