Hello, got a crash using 1.22-ctest23.
The crash happens aprox 75% of the time when using a Mystcraft linking book. I think it might be related to the LookingGlass mod used to show the link in location. It throws a number of ArrayIndexOutOfBoundsException before the crash.
Can you post the crash report instead of the log?
I've had a lot of bad experiences with MystCraft, mainly Pahimar refusing to fix major bugs and performance issues. Hopefully this isn't a bug with MystCraft or you may be out of luck