on_gui_click returned an error
I added a workaround after line 85:
if not inserter or not inserter.valid then
return {
base = {x=0, y=0},
base_offset = {x=0, y=0},
drop = {x=0, y=0},
drop_offset = {x=0, y=0},
pickup = {x=0, y=0}
}
end
It seems to be working for now. Please either do the same or fix it yourself.