If you are updating your MultiCoder from an earlier version, it's quite possible that the previous booking-list XML's will not load.
These XML files are usually found in the working directory for the corresponding MultiCoder instance (Default: [Digas Directory]\Files\DeviceID[n]\BookingLists)
Regarding an update from Build 71 to 87, this can be remedied by deleting the DTD (XML Schema) files in the MultiCoder working directory (both DeviceId root and in the BookingLists directory) as well as modifying the existing booking-list XML's by adding "<ReferenceNumber>0</ReferenceNumber>" as subnode to each <booking> node so that it looks something like this;


A compatible DTD will be regenerated by the MultiCoder and the existing Booking-lists should then be compatible.