Chunks deleted/corrupted

[opa334]

Hello, I and my friend playing a LAN world (direwolf20), we have an updated minecraftforge version and optifine installed, but after a while (4-5 hours) a few chunks are corrupted. (Pics: http://s14.directupload.net/images/130220/n3p7dnzv.png http://s14.directupload.net/images/130220/n3p7dnzv.png)
I get this error:

2013-02-20 15:23:02 [INFO] [STDOUT] Wrong location! iq['opa334'/303, l='FTB Survival', x=6,48, y=79,53, z=353,92]
2013-02-20 15:23:02 [INFO] [STDERR] java.lang.Exception: Stack trace
2013-02-20 15:23:02 [INFO] [STDERR]    at java.lang.Thread.dumpStack(Unknown Source)
2013-02-20 15:23:02 [INFO] [STDERR]    at zz.a(Chunk.java:923)
2013-02-20 15:23:02 [INFO] [STDERR]    at yc.a(World.java:2338)
2013-02-20 15:23:02 [INFO] [STDERR]    at in.a(WorldServer.java:647)
2013-02-20 15:23:02 [INFO] [STDERR]    at yc.g(World.java:2255)
2013-02-20 15:23:02 [INFO] [STDERR]    at yc.h(World.java:2109)
2013-02-20 15:23:02 [INFO] [STDERR]    at in.h(WorldServer.java:516)
2013-02-20 15:23:02 [INFO] [STDERR]    at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:680)
2013-02-20 15:23:02 [INFO] [STDERR]    at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:599)
2013-02-20 15:23:02 [INFO] [STDERR]    at bdz.q(IntegratedServer.java:123)
2013-02-20 15:23:02 [INFO] [STDERR]    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:497)
2013-02-20 15:23:02 [INFO] [STDERR]    at fy.run(SourceFile:849)

Any1 have the same problem or a solution?
I can't play FTB when my Chunks are always crashing

PS: Full report at: http://pastebin.com/WqzeMqZr
PPS: Sorry for the bad english.