Error but i don't know what error...

My server is crashing every 2 minutes but i don't know why
What plugin is doing that ? This is a log:

Item entity 6759 has no item?!
2013-01-03 11:41:39 [SEVERE] net.minecraft.server.v1_4_6.ReportedException: Loading entity NBT
2013-01-03 11:41:39 [SEVERE] at net.minecraft.server.v1_4_6.Entity.e(Entity.java:1202)
2013-01-03 11:41:39 [SEVERE] at net.minecraft.server.v1_4_6.EntityTypes.a(SourceFile:122)
2013-01-03 11:41:39 [SEVERE] at net.minecraft.server.v1_4_6.ChunkRegionLoader.loadEntities(ChunkRegionLoader.java:333)
2013-01-03 11:41:39 [SEVERE] at org.bukkit.craftbukkit.v1_4_6.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:47)
2013-01-03 11:41:39 [SEVERE] at org.bukkit.craftbukkit.v1_4_6.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:13)
2013-01-03 11:41:39 [SEVERE] at org.bukkit.craftbukkit.v1_4_6.util.AsynchronousExecutor$Task.finish(AsynchronousExecutor.java:179)
2013-01-03 11:41:39 [SEVERE] at org.bukkit.craftbukkit.v1_4_6.util.AsynchronousExecutor.finishActive(AsynchronousExecutor.java:287)
2013-01-03 11:41:39 [SEVERE] at org.bukkit.craftbukkit.v1_4_6.chunkio.ChunkIOExecutor.tick(ChunkIOExecutor.java:30)
2013-01-03 11:41:39 [SEVERE] at net.minecraft.server.v1_4_6.MinecraftServer.r(MinecraftServer.java:537)
2013-01-03 11:41:39 [SEVERE] at net.minecraft.server.v1_4_6.DedicatedServer.r(DedicatedServer.java:224)
2013-01-03 11:41:39 [SEVERE] at net.minecraft.server.v1_4_6.MinecraftServer.q(MinecraftServer.java:494)
2013-01-03 11:41:39 [SEVERE] at net.minecraft.server.v1_4_6.MinecraftServer.run(MinecraftServer.java:427)
2013-01-03 11:41:39 [SEVERE] at net.minecraft.server.v1_4_6.ThreadServerApplication.run(SourceFile:849)
2013-01-03 11:41:39 [SEVERE] Caused by: java.lang.NullPointerException
2013-01-03 11:41:39 [SEVERE] at net.minecraft.server.v1_4_6.DataWatcher.watch(SourceFile:138)
2013-01-03 11:41:39 [SEVERE] at net.minecraft.server.v1_4_6.EntityItem.setItemStack(EntityItem.java:277)
2013-01-03 11:41:39 [SEVERE] at net.minecraft.server.v1_4_6.EntityItem.a(EntityItem.java:193)
2013-01-03 11:41:39 [SEVERE] at net.minecraft.server.v1_4_6.Entity.e(Entity.java:1156)
2013-01-03 11:41:39 [SEVERE] ... 12 more
2013-01-03 11:41:39 [SEVERE] Encountered an unexpected exception ReportedException
net.minecraft.server.v1_4_6.ReportedException: Loading entity NBT
at net.minecraft.server.v1_4_6.Entity.e(Entity.java:1202)
at net.minecraft.server.v1_4_6.EntityTypes.a(SourceFile:122)
at net.minecraft.server.v1_4_6.ChunkRegionLoader.loadEntities(ChunkRegionLoader.java:333)
at org.bukkit.craftbukkit.v1_4_6.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:47)
at org.bukkit.craftbukkit.v1_4_6.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:13)
at org.bukkit.craftbukkit.v1_4_6.util.AsynchronousExecutor$Task.finish(AsynchronousExecutor.java:179)
at org.bukkit.craftbukkit.v1_4_6.util.AsynchronousExecutor.finishActive(AsynchronousExecutor.java:287)
at org.bukkit.craftbukkit.v1_4_6.chunkio.ChunkIOExecutor.tick(ChunkIOExecutor.java:30)
at net.minecraft.server.v1_4_6.MinecraftServer.r(MinecraftServer.java:537)
at net.minecraft.server.v1_4_6.DedicatedServer.r(DedicatedServer.java:224)
at net.minecraft.server.v1_4_6.MinecraftServer.q(MinecraftServer.java:494)
at net.minecraft.server.v1_4_6.MinecraftServer.run(MinecraftServer.java:427)
at net.minecraft.server.v1_4_6.ThreadServerApplication.run(SourceFile:849)
Caused by: java.lang.NullPointerException
at net.minecraft.server.v1_4_6.DataWatcher.watch(SourceFile:138)
at net.minecraft.server.v1_4_6.EntityItem.setItemStack(EntityItem.java:277)
at net.minecraft.server.v1_4_6.EntityItem.a(EntityItem.java:193)
at net.minecraft.server.v1_4_6.Entity.e(Entity.java:1156)
... 12 more
2013-01-03 11:41:39 [SEVERE] This crash report has been saved to: /home/markrosa/4544/./crash-reports/crash-2013-01-03_11.41.39-server.txt

 

Can you stop your server. Clear your server.log. Start your server again, and send us your server.log.

In addition: server specs, plugin list, plugin versions, etc.
And of course the crash report "/home/markrosa/4544/./crash-reports/crash-2013-01-03_11.41.39-server.txt"

 

Im getting this same exact error too! people cant even connect to the server! It crashes instantly when you connect! Please help, my server is very popular. I get 50+ players on daily and now they are all going to leave.

 

I get the same error too. The server works for a few hours and then crashes. My console still thinks its up, I use multicraft. This is the link http://pastebin.com/M239VqL8