I tried to use an Assembler to place a tin cable, and this happened.
Mods loaded: 14
ModLoader 1.2.5
mod_CodeChickenCore 0.5.2
mod_MinecraftForge 3.1.2.94
mod_NotEnoughItems 1.2.2
mod_ImmibisCore 48.1.0
mod_IC2 v1.95
mod_RedPowerControl 2.0pr5b1
mod_RedPowerCore 2.0pr5b1
mod_RedPowerLighting 2.0pr5b1
mod_RedPowerLogic 2.0pr5b1
mod_RedPowerMachine 2.0pr5b1
mod_RedPowerWiring 2.0pr5b1
mod_RedPowerWorld 2.0pr5b1
mod_TubeStuff 48.1.0
Minecraft has crashed!
----------------------
Minecraft has stopped running because it encountered a problem.
--- BEGIN ERROR REPORT e520ed53 --------
Generated 4/05/12 1:40 PM
Minecraft: Minecraft 1.2.5
OS: Windows Vista (x86) version 6.0
Java: 1.7.0_03, Oracle Corporation
VM: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
LWJGL: 2.4.2
OpenGL: Intel 965/963 Graphics Media Accelerator version 1.5.0 - Build 7.14.10.1295, Intel
java.lang.NullPointerException
at xd.a(World.java:3825)
at ic2.common.ItemCable.a(ItemCable.java:114)
at eloraam.machine.TileDeployBase.tryUseItemStack(TileDeployBase.java:151)
at eloraam.machine.TileAssemble.enableTowardsActive(TileAssemble.java:193)
at eloraam.machine.TileAssemble.updateCurrentStrength(TileAssemble.java:116)
at eloraam.core.RedPowerLib.updateCurrent(RedPowerLib.java:700)
at eloraam.wiring.TileWiring.onBlockNeighborChange(TileWiring.java:138)
at eloraam.core.BlockMultipart.a(BlockMultipart.java:29)
at eloraam.core.RedPowerLib.notifyBlock(RedPowerLib.java:42)
at eloraam.core.RedPowerLib.updateIndirectNeighbors(RedPowerLib.java:55)
at eloraam.core.TileExtended.updateBlockChange(TileExtended.java:75)
at eloraam.control.TileIOExpander.onTileTick(TileIOExpander.java:109)
at eloraam.core.TileExtended.n_(TileExtended.java:104)
at xd.n(World.java:2071)
at net.minecraft.client.Minecraft.k(Minecraft.java:1861)
at net.minecraft.client.Minecraft.x(Minecraft.java:819)
at net.minecraft.client.Minecraft.run(Minecraft.java:747)
at java.lang.Thread.run(Unknown Source)
--- END ERROR REPORT c75260ed ----------
Edit: Forgot IC2 version in title.