High levels in 13-channel worlds can't save the Miwok boys

Describe the problem. Be as specific as possible!:

The channel designated for the high-level version of the Miwok Boys event is 18.
Or possibly 17 if the usual offset applies.
Either way, in the five worlds that only have 13 channels, this channel doesn't exist and so high-level characters can't participate in the event.

 Images of problem

Clicking "Next" leads to this:


When you click "OK", the dialog window closes, and nothing happens.