Hi Seceroth,
Thanks for reporting this issue and including the error details!
ATRM currently supports and is tested with Vanilla, Space Age, Krastorio 2, Space Exploration, and K2SE.
Krastorio 2 Spaced Out (K2SO) is not part of our current compatibility testing and wasn't originally planned as a supported configuration.
However, I'm happy to take a closer look at the issue. The error already gives us a useful starting point, but K2SO introduces changes that may require additional compatibility adjustments.
Please understand that investigating and testing this combination will take some time, and I can't promise full K2SO compatibility at this stage.
Thanks again for bringing this to my attention!
MoSII2710