I got this message and was kicked back out to the main menu during a singleplayer game:

The mod Schall Tank Woodcutting (1.1.1) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event SchallTankWoodcutting::on_entity_damaged (ID 102)
Item stack count has to be a positive integer.
stack traceback:
[C]: in function 'spill_item_stack'
_ _SchallTankWoodcutting_ _/control.lua:57: in function 'car_harvest'
_ _SchallTankWoodcutting_ _/control.lua:73: in function
<_ _SchallTankWoodcutting_ _/control.lua:72>

It's been a while but I figured out some more context - it specifically crashes out when a vehicle collides with a meteor object from Space Exploration.

Should be fixed in my fork of this mod (see here for more details)!

Just uploaded 1.1.2 & 2.0.0 updates, hope the above bug can be dealt with them.

i received one very similar to this with a slightly different lua and id but seemingly related.

The mod Schall Tank Woodcutting (2.0.0) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event SchallTankWoodcutting::on_entity_damaged (ID 111)
SchallTankWoodcutting/control.lua:48: attempt to index local 'char' (a nil value)
stack traceback:
SchallTankWoodcutting/control.lua:48: in function 'car_harvest'
SchallTankWoodcutting/control.lua:89: in function <SchallTankWoodcutting/control.lua:88>

Got the same error as snakeanarchy. It popped up when I had to jump out of my car because i hit a dead end in a forest and had a huge swarm of biters on my tail. Perhaps it's because the car tried to collect wood without a driver?

Error while running event SchallTankWoodcutting::on_entity_damaged (ID 111)
SchallTankWoodcutting/control.lua:48: attempt to index local 'char' (a nil value)
stack traceback:
SchallTankWoodcutting/control.lua:48: in function 'car_harvest'
SchallTankWoodcutting/control.lua:89: in function <SchallTankWoodcutting/control.lua:88>

This is a new bug, caused by different return value type from the API when remote driving.
Possibly a duplicate report.
Please check 2.0.1 update.