Trade-o-mat Crash

2013-07-31 20:27:04 [SEVERE] Encountered an unexpected exception NoClassDefFoundError
java.lang.NoClassDefFoundError: net/minecraft/server/integrated/IntegratedServer
        at ic2.core.block.personal.TileEntityTradeOMat.permitsAccess(TileEntityTradeOMat.java:241)
        at ic2.core.block.personal.TileEntityTradeOMat.getGuiContainer(TileEntityTradeOMat.java:264)
        at ic2.core.Platform.launchGui(Platform.java:65)
        at ic2.core.block.BlockMultiID.func_71903_a(BlockMultiID.java:229)
        at ic2.core.block.personal.BlockPersonal.func_71903_a(BlockPersonal.java:136)
        at net.minecraft.item.ItemInWorldManager.func_73078_a(ItemInWorldManager.java:412)
        at net.minecraft.network.NetServerHandler.func_72472_a(NetServerHandler.java:553)
        at net.minecraft.network.packet.Packet15Place.func_73279_a(SourceFile:58)
        at net.minecraft.network.TcpConnection.func_74428_b(TcpConnection.java:461)
        at net.minecraft.network.NetServerHandler.func_72570_d(NetServerHandler.java:134)
        at net.minecraft.network.NetworkListenThread.func_71747_b(NetworkListenThread.java:53)
        at net.minecraft.server.dedicated.DedicatedServerListenThread.func_71747_b(SourceFile:30)
        at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:677)
        at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:275)
        at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:573)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:470)
        at net.minecraft.server.ThreadMinecraftServer.run(SourceFile:573)
Caused by: java.lang.ClassNotFoundException: net.minecraft.server.integrated.IntegratedServer
        at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:238)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        ... 17 more
Caused by: java.lang.RuntimeException: Attempted to load class bjg for invalid side SERVER
        at cpw.mods.fml.common.asm.transformers.SideTransformer.transform(SideTransformer.java:50)
        at cpw.mods.fml.relauncher.RelaunchClassLoader.runTransformers(RelaunchClassLoader.java:352)
        at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:225)
        ... 19 more