Since i have no clue how to paste a picture here im just rewriting it:

"The mod LTN Combinator for 1.1(1.1.1) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event LTN_Combinator_Fix::on_gui_elem_changed(ID67)
LTN_Combinator_Fix/scripts/ltnc-gui.lua:629: attempt to index field 'combinator' (a nil value)
stack traceback:
LTN_Combinator_Fix/scripts/ltnc-gui.lua:629: in function '?'
LTN_Combinator_Fix/scripts/ltnc-events.lua:38: in function
<LTN_Combinator_Fix/scripts/ltnc-events.lua:36>"

This happend 1.1.19, windows 10, multiplayer.
Edit, miswrote and forgot some things.

Since i have no clue how to paste a picture here im just rewriting it:

"The mod LTN Combinator for 1.1(1.1.1) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event LTN_Combinator_Fix::on_gui_elem_changed(ID67)
LTN_Combinator_Fix/scripts/ltnc-gui.lua:629: attempt to index field 'combinator' (a nil value)
stack traceback:
LTN_Combinator_Fix/scripts/ltnc-gui.lua:629: in function '?'
LTN_Combinator_Fix/scripts/ltnc-events.lua:38: in function
<LTN_Combinator_Fix/scripts/ltnc-events.lua:36>"

This happend 1.1.19, windows 10, multiplayer.
Edit, miswrote and forgot some things.

Please also note that everything that is written Bulk has "__" infront and behind them.

(Ignore this, i accidently responded)

I just had this problem, or at least a very similar one:
The mod LTN Combinator for 1.1 (1.1.1) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event LTN_Combinator_Fix::on_gui_click (ID 1)
LTN_Combinator_Fix/scripts/ltnc-gui.lua:579: attempt to index field 'combinator' (a nil value)
stack traceback:
LTN_Combinator_Fix/scripts/ltnc-gui.lua:579: in function '?'
LTN_Combinator_Fix/scripts/ltnc-events.lua:23: in function <LTN_Combinator_Fix/scripts/ltnc-events.lua:21>

What led to the problem was: My game was lagging. I clicked aimlessly, hit an LTN combinator. The window opened. I pressed E to close it; it didn't close immediately (because lag). I clicked aimlessly again, hitting one of the checkboxes in the combinator GUI. I then lost connection. When I asked the server host about it later, he told me it crashed with the above error message.

I assume the error happened because I attempted to change a setting in a GUI that I had already supposedly closed.