Server crashing when people join

[SuzmAJohn]

Title: Server crashing when people join

Version: 3.1.2

OS: Windows 7 Ultimate

Java Version: Newest

Description of Problem:

When some users join (not all) it crash

Error Messages:

Error Log:

2012-08-12 17:51:16 [iNFO] Sending serverside check to: EpicFlamingos

2012-08-12 17:51:16 [sEVERE] java.lang.NullPointerException

2012-08-12 17:51:16 [sEVERE] at org.bukkit.craftbukkit.event.CraftEventFactory.callBlockPlaceEvent(CraftEventFactory.java:98)

2012-08-12 17:51:16 [sEVERE] at buildcraft.factory.TileQuarry.doWork(TileQuarry.java:210)

2012-08-12 17:51:16 [sEVERE] at buildcraft.api.PowerProvider.update(PowerProvider.java:50)

2012-08-12 17:51:16 [sEVERE] at buildcraft.core.TileBuildCraft.q_(TileBuildCraft.java:54)

2012-08-12 17:51:16 [sEVERE] at buildcraft.factory.TileQuarry.q_(TileQuarry.java:136)

2012-08-12 17:51:16 [sEVERE] at net.minecraft.server.World.tickEntities(World.java:1190)

2012-08-12 17:51:16 [sEVERE] at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:569)

2012-08-12 17:51:16 [sEVERE] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:467)

2012-08-12 17:51:16 [sEVERE] at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)

2012-08-12 17:51:16 [sEVERE] Unexpected exception

java.lang.NullPointerException

at org.bukkit.craftbukkit.event.CraftEventFactory.callBlockPlaceEvent(CraftEventFactory.java:98)

at buildcraft.factory.TileQuarry.doWork(TileQuarry.java:210)

at buildcraft.api.PowerProvider.update(PowerProvider.java:50)

at buildcraft.core.TileBuildCraft.q_(TileBuildCraft.java:54)

at buildcraft.factory.TileQuarry.q_(TileQuarry.java:136)

at net.minecraft.server.World.tickEntities(World.java:1190)

at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:569)

at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:467)

at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)

2012-08-12 17:51:31 [iNFO] Connection reset