Crashes when Ghost creeper spawn or possibly despawns I believe.

Server crashlog:
http://pastebin.com/mjR07HUJ

OpenEye:

http://openeye.openmods.info/crashes/aa43cf88fe497aa569732422ab42bd36

Similar to the issue here which doesn't explicitly say Ghost Creeper. http://www.minecraftforum.net/forums/mapping-and-modding/minecraft-mods/2111959-1-7-x-elemental-creepers-rebooted?comment=65

Should be fixed with 4ad4e5b