Issue with Plugin "BKCommonLib"

[BOfH85]

Hi there, I'm Rick, Sysadmin and Programmer and Minecraft Enthusiast since 2014. Wanted to try out Fiddle but it doesn't work together with a plugin I am using, "BKCommonLib". (Which is used for the Plugin "Train Carts").
All other plugins which I am still using are loading and working great but this one not.

I know this is still in development but if you want this Mod to be a fully compatible Drop-In Replacement of Paper than this should be adressed somehow.

Here is the log from the Server Startup:
Link