Thanks for reporting, definitely a bug here, should be fixed in 0.3.14.
I don't understand how the Will-o'-the-wisps Mod can have a problem with a circuit mod ...
That mod adds a different surface/world to the game, the one you build circuit elements on, and teleports player there.
When green wisps randomly choose to follow player, forgot to add a check that player is on the same surface (default factorio only has one), and issuing "go to player" command when player character is not in the same world causes that error linked above, as there's no possible way to reach them there for units.
So while it might look like a simple circuit mod, it's not just adding a new entity or modifying existing ones, like most circuit network mods do, but actually adds a whole pocket dimension for you to build stuff in :)