Real short answer, I do not know why you are having issues.
It just seems to have been some connection to old model of the IX for functions to the schnelboot, causing CTD once broken. I do not have this mod and do not know how it is set up.
Just out of curiosity, do you have a working IX and does the model work properly.
You might check out this thread :
https://www.subsim.com/radioroom//showthread.php?t=228495
Kendrass indicated he had to disable mods in order to get this going.