I was trying to run a Yogscast Complete server and it won't work?

Here is the crash log ---- Minecraft Crash Report ----
// Who set us up the TNT?

Time: 7/7/14 12:36 AM
Description: Ticking entity

java.lang.NullPointerException
at aiv.a(SourceFile:36)
at ain.a(SourceFile:87)
at aet.a(SourceFile:426)
at jr.a(SourceFile:168)
at adr.a(SourceFile:732)
at jr.c(SourceFile:105)
at jr.d(SourceFile:116)
at abw.e(SourceFile:289)
at acl.<init>(SourceFile:32)
at abw.a(SourceFile:2241)
at rf.a(SourceFile:78)
at rf.a(SourceFile:82)
at qm.c(SourceFile:41)
at pt.a(SourceFile:91)
at og.bi(SourceFile:410)
at of.c(SourceFile:1289)
at og.c(SourceFile:292)
at tm.c(SourceFile:24)
at tw.c(SourceFile:141)
at of.l_(SourceFile:1176)
at og.l_(SourceFile:169)
at tm.l_(SourceFile:29)
at tw.l_(SourceFile:197)
at abw.a(SourceFile:1349)
at js.a(SourceFile:479)
at abw.g(SourceFile:1327)
at abw.h(SourceFile:1234)
at js.h(SourceFile:364)
at net.minecraft.server.MinecraftServer.t(SourceFile:471)
at is.t(SourceFile:263)
at net.minecraft.server.MinecraftServer.s(SourceFile:406)
at net.minecraft.server.MinecraftServer.run(SourceFile:340)
at hi.run(SourceFile:583)

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
at aiv.a(SourceFile:36)
at ain.a(SourceFile:87)
at aet.a(SourceFile:426)
at jr.a(SourceFile:168)
at adr.a(SourceFile:732)
at jr.c(SourceFile:105)
at jr.d(SourceFile:116)
at abw.e