Its neat to hear people using this mod.. To be honest it was initially done for a friend and myself to play with.. didn't even notice it had gotten so many downloads!
For your error.. looks like there was a 1.2.19 update for K2.. maybe it will fix your issue?
I looked at the source for both 1.2.18 and 1.2.19 and wasn't seeing anything that would directly cause conflict..
I did notice I never added an incompatibility flag for this mod, as I mentioned didn't realize people would actually use it...
however.. Make sure you are not running both my mod and the original QOL mod by Aidiakapi that could lead to conflict you are seeing.
This mod replaces that mod and they should not be used together.
If you are still having issues than its possibly a conflict with one of the other mods you have loaded?