I can't join my own server

[SonicWindZz]

I played on my ftb server a long time and when i played it suddenly crashed saying "internal server error" and in my server is said this:
WARNING] Failed to handle packet for SonicWindZz/80.60.64.133: java.lang.ArithmeticException: / by zero
java.lang.ArithmeticException: / by zero
at thaumcraft.common.items.ItemElementalPickaxe.a(ItemElementalPickaxe.java:148)
at ur.a(SourceFile:289)
at qw.j(SourceFile:192)
at qx.c(EntityPlayer.java:558)
at md.j_(EntityLiving.java:843)
at qx.j_(EntityPlayer.java:328)
at iq.g(EntityPlayerMP.java:286)
at iv.a(NetServerHandler.java:310)
at eb.a(SourceFile:136)
at cg.b(TcpConnection.java:458)
at iv.d(NetServerHandler.java:136)
at iw.b(NetworkListenThread.java:57)
at ht.b(SourceFile:30)
at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:703)
at ho.r(DedicatedServer.java:269)
at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:599)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:497)
at fy.run(SourceFile:849)
Help Please