Cross post since the error mentions both mods:

https://mods.factorio.com/mod/Rampant/discussion/5ec422843a36ee000c5f3ab8

I could try to fix that on my end but really its down to either Rampant adding a nil check or Klonan adding a method to establish the road network without faking events.

It's probably best if you also send item data in the raise_event call, iirc it's required in the docs.

#blameKlonan he gave me the code but yeah the the doc states that item is required but only for robot built tiles. Player built tiles have the item field marked as optional.
https://lua-api.factorio.com/latest/events.html#on_player_built_tile
https://lua-api.factorio.com/latest/events.html#on_robot_built_tile

It will get a fix but, I will wait until the next base game update since the event system is undergoing some changes.

Not going to try to fix something I know I have to change in a few days anyway.

This should now be fixed.