And the client-side laser crash:
[B#439] ---- Minecraft Crash Report ----
[B#439] // I let you down. Sorry
[B#439]
[B#439] Time: 7/8/14 10:26 AM
[B#439] Description: Exception in server tick loop
[B#439]
[B#439] java.lang.NoSuchMethodError: com.mojang.authlib.GameProfile.getId()Ljava/lang/String;
[B#439] at ic2classic.core.network.NetworkManager.initiateItemEvent(NetworkManager.java:115)
[B#439] at ic2classic.core.item.tool.ItemToolMiningLaser.func_77659_a(ItemToolMiningLaser.java:59)
[B#439] at net.minecraft.item.ItemStack.func_77957_a(ItemStack.java:144)
[B#439] at net.minecraft.server.management.ItemInWorldManager.func_73085_a(ItemInWorldManager.java:316)
[B#439] at net.minecraft.network.NetHandlerPlayServer.func_147346_a(NetHandlerPlayServer.java:538)
[B#439] at net.minecraft.network.play.client.C08PacketPlayerBlockPlacement.func_148833_a(SourceFile:60)
[B#439] at net.minecraft.network.play.client.C08PacketPlayerBlockPlacement.func_148833_a(SourceFile:9)
[B#439] at net.minecraft.network.NetworkManager.func_74428_b(NetworkManager.java:212)
[B#439] at net.minecraft.network.NetworkSystem.func_151269_c(NetworkSystem.java:165)
[B#439] at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:659)
[B#439] at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:547)
[B#439] at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:111)
[B#439] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:427)
[B#439] at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:685)