I've been attempting to use simple spawners to populate ragnarok with some extra creatures in single player, however whenever logging in after placing a spawner of any kind the game presents a fatal error and crashes. The only way to play again is to delete the entire save file and start again. I have added the preventhibernation string to the startup as suggested in the mod description.

Edit: Through testing i have confirmed this is not a mod conflict or result of using modded creatures in the spawners. The error occurs even when only using vanilla creatures.