çağlar

My friend cannot connect to my server. and he got that screen. we got the same version of tekkit lite. how can ı fix this -- Head -- Stacktrace: at asw.d(SourceFile:35) at asw.b(SourceFile:23) at net.minecraft.client.Minecraft.a(Minecraft.java:2080) at net.minecraft.client.Minecraft.a(Minecraft.java:2025) at cpw.mods.fml.client.FMLClientHandler.disconnectIDMismatch(FMLClientHandler.java:529) at cpw.mods.fml.common.FMLCommonHandler.disconnectIDMismatch(FMLCommonHandler.java:464) at cpw.mods.fml.common.network.ModIdMapPacket.execute(ModIdMapPacket.java:89) at cpw.mods.fml.common.network.FMLNetworkHandler.handleFMLPacket(FMLNetworkHandler.java:102) at cpw.mods.fml.common.network.FMLNetworkHandler.handlePacket250Packet(FMLNetworkHandler.java:67) at ayh.a(NetClientHandler.java:1483) at di.a(SourceFile:59) at cg.b(TcpConnection.java:458) at ayh.d(NetClientHandler.java:240) at ayk.c(GuiConnecting.java:49) -- Affected screen -- Details: Screen name: ~~ERROR~~ NullPointerException: null asy at asw.d(SourceFile:35) at asw.b(SourceFile:23) at net.minecraft.client.Minecraft.a(Minecraft.java:2080) at net.minecraft.client.Minecraft.a(Minecraft.java:2025) at cpw.mods.fml.client.FMLClientHandler.disconnectIDMismatch(FMLClientHandler.java:529) at cpw.mods.fml.common.FMLCommonHandler.disconnectIDMismatch(FMLCommonHandler.java:464) at cpw.mods.fml.common.network.ModIdMapPacket.execute(ModIdMapPacket.java:89) at cpw.mods.fml.common.network.FMLNetworkHandler.handleFMLPacket(FMLNetworkHandler.java:102) at cpw.mods.fml.common.network.FMLNetworkHandler.handlePacket250Packet(FMLNetworkHandler.java:67) at ayh.a(NetClientHandler.java:1483) at di.a(SourceFile:59) at cg.b(TcpConnection.java:458) at ayh.d(NetClientHandler.java:240) at ayk.c(GuiConnecting.java:49) at net.minecraft.client.Minecraft.l(Minecraft.java:1539) at net.minecraft.client.Minecraft.J(Minecraft.java:848) at net.minecraft.client.Minecraft.run(Minecraft.java:773) at java.lang.Thread.run(Unknown Source)