Trying to remove some premade tunnels showing up above the ground, using worldedit.

Minecraft has crashed!
----------------------

Minecraft has stopped running because it encountered a problem; Unexpected error

A full error report has been saved to C:\Users\martin\AppData\Roaming\.minecraft\crash-reports\crash-2012-12-10_15.58.14-client.txt - Please include a copy of that file (Not this screen!) if you report this crash to anyone; without it, they will not be able to help fix the crash

— BEGIN ERROR REPORT fba0a045 --------
Full report at:
C:\Users\martin\AppData\Roaming\.minecraft\crash-reports\crash-2012-12-10_15.58.14-client.txt
Please show that file to Mojang, NOT just this screen!

Generated 10-12-12 15:58

– Head –
Stacktrace:
at bdd.a(SourceFile:25)
at bdd.a(SourceFile:10)
at bdl.a(SourceFile:103)
at bdl.a(SourceFile:96)
at bak.a(SourceFile:325)
at bac.a(SourceFile:897)

– Affected level –
Details:
Level name: MpServer
All players: 1 total; [ayk['Fungreenfox'/1397613, l='MpServer', x=-650,68, y=53,54, z=450,29]]
Chunk stats: MultiplayerChunkCache: 446
Level seed: 0
Level generator: ID 01 - flat, ver 0. Features enabled: false
Level generator options:
Level spawn location: World: (-1752,52,-467), Chunk: (at 8,3,13 in -110,-30; contains blocks -1760,0,-480 to -1745,255,-465), Region: (-4,-1; contains chunks -128,-32 to -97,-1, blocks -2048,0,-512 to -1537,255,-1)
Level time: 640290 game time, 640290 day time
Level dimension: 0
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: false
Forced entities: 1 total; [ayk['Fungreenfox'/1397613, l='MpServer', x=-650,68, y=53,54, z=450,29]]
Retry entities: 0 total; []
Stacktrace:
at ayh.a(SourceFile:290)
at net.minecraft.client.Minecraft.b(SourceFile:1870)
at net.minecraft.client.Minecraft.run(SourceFile:548)
at java.lang.Thread.run(Unknown Source)

– System Details –
Details:
Minecraft Version: 1.4.5
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.7.0_09, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 246107480 bytes (234 MB) / 400424960 bytes (381 MB) up to 954466304 bytes (910 MB)
JVM Flags: 2 total; -Xms512m -Xmx1024m
AABB Pool Size: 851 (47656 bytes; 0 MB) allocated, 2 (112 bytes; 0 MB) used
Suspicious classes: ~_ERROR~ NoClassDefFoundError: com/pclewis/mcpatcher/mod/TileOverride$1
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
LWJGL: 2.4.2
OpenGL: GeForce GTX 680/PCIe/SSE2 GL version 4.2.0, NVIDIA Corporation
Is Modded: Very likely; Jar signature invalidated
Type: Client (map_client.txt)
Texture Pack: BSpecial_Supertex.zip
Profiler Position: N/A (disabled)
Vec3 Pool Size: 183 (10248 bytes; 0 MB) allocated, 29 (1624 bytes; 0 MB) used

java.lang.ClassCastException: akc cannot be cast to ajd
at bdd.a(SourceFile:25)
at bdd.a(SourceFile:10)
at bdl.a(SourceFile:103)
at bdl.a(SourceFile:96)
at bak.a(SourceFile:325)
at bac.a(SourceFile:897)
at bac.b(SourceFile:751)
at net.minecraft.client.Minecraft.J(SourceFile:604)
at net.minecraft.client.Minecraft.run(SourceFile:534)
at java.lang.Thread.run(Unknown Source)
— END ERROR REPORT e04724c7 ----------