This is in my own base, with an MFR fertilizer on to Forestry saplings. As seen on the console (not visible to players): 18:00:59 [INFO] CRASH @ (redacted) 18:00:59 [SEVERE] java.lang.NullPointerException 18:00:59 [SEVERE] at denoflionsx.minefactoryreloaded.modhelpers.forestry.trees.FertilizableForestryTree.fertilize(FertilizableForestryTree.java:28) 18:00:59 [SEVERE] at powercrystals.minefactoryreloaded.tile.machine.TileEntityFertilizer.activateMachine(TileEntityFertilizer.java:87) 18:00:59 [SEVERE] at powercrystals.minefactoryreloaded.tile.base.TileEntityFactoryPowered.func_70316_g(TileEntityFactoryPowered.java:136) 18:00:59 [SEVERE] at net.minecraft.world.World.func_72939_s(World.java:2782) 18:00:59 [SEVERE] at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:883) 18:00:59 [SEVERE] at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:330) 18:00:59 [SEVERE] at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:777) 18:00:59 [SEVERE] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:659) 18:00:59 [SEVERE] at net.minecraft.server.ThreadMinecraftServer.run(ThreadMinecraftServer.java:16)
WELL it's not entirely server-breaking and no one really wants to touch a modpack that seems to be mostly stable.
