The "Unhandled Exception" error comes from Windows and relates to the USB driver for the IC on Maxim EVKits. It is normally caused by power cycling the EVKit when the GUI is running, and is easily avoided by using the following sequence.
Power on both EVKits (serializer and deserializer). Connect USB to one of the EVKits. Start the GUI.
If this error occurs during normal use, close the GUI, cycle power on both EVKits and start the GUI.