mjb4

Same issue here with minecraft server version 1.11.1 (but not with version 1.11) on linux.
Asked for help here already: http://gaming.stackexchange.com/questions/295073/ticking-entity-error-on-minecraft-server
If necessary I'll upload a world file too.

Here the error log:
---- Minecraft Crash Report ----
// I blame Dinnerbone.

Time: 12/20/16 6:32 PM
Description: Ticking entity

java.lang.NullPointerException: Ticking entity
    at sn.al(SourceFile:1023)
    at sn.ak(SourceFile:1009)
    at sw.a(SourceFile:203)
    at sn.a(SourceFile:784)
    at sw.g(SourceFile:1585)
    at sw.n(SourceFile:1870)
    at sx.n(SourceFile:499)
    at sk.n(SourceFile:144)
    at ww.n(SourceFile:39)
    at wx.n(SourceFile:82)
    at sw.A_(SourceFile:1703)
    at sx.A_(SourceFile:282)
    at ajs.a(SourceFile:1517)
    at lw.a(SourceFile:718)
    at ajs.h(SourceFile:1495)
    at ajs.k(SourceFile:1378)
    at lw.k(SourceFile:551)
    at net.minecraft.server.MinecraftServer.D(SourceFile:634)
    at lh.D(SourceFile:335)
    at net.minecraft.server.MinecraftServer.C(SourceFile:562)
    at net.minecraft.server.MinecraftServer.run(SourceFile:466)
    at java.lang.Thread.run(Thread.java:745)


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

-- Head --
Thread: Server thread
Stacktrace:
    at sn.al(SourceFile:1023)
    at sn.ak(SourceFile:1009)
    at sw.a(SourceFile:203)
    at sn.a(SourceFile:784)
    at sw.g(SourceFile:1585)
    at sw.n(SourceFile:1870)
    at sx.n(SourceFile:499)
    at sk.n(SourceFile:144)
    at ww.n(SourceFile:39)
    at wx.n(SourceFile:82)
    at sw.A_(SourceFile:1703)
    at sx.A_(SourceFile:282)
    at ajs.a(SourceFile:1517)
    at lw.a(SourceFile:718)
    at ajs.h(SourceFile:1495)

-- Entity being ticked --
Details:
    Entity Type: minecraft:chicken (wx)
    Entity ID: 30
    Entity Name: Chicken
    Entity's Exact location: -328.71, 42.65, 146.03
    Entity's Block location: World: (-329,42,146), Chunk: (at 7,2,2 in -21,9; contains blocks -336,0,144 to -321,255,159), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
    Entity's Momentum: 0.00, -0.05, -0.07
    Entity's Passengers: [aao['Zombie'/31, l='worlds/premium welt', x=-328.76, y=43.05, z=145.99]]
    Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
    at ajs.k(SourceFile:1378)
    at lw.k(SourceFile:551)

-- Affected level --
Details:
    Level name: worlds/premium welt
    All players: 0 total; []
    Chunk stats: ServerChunkCache: 625 Drop: 0
    Level seed: -4260957353016816717
    Level generator: ID 00 - default, ver 1. Features enabled: true
    Level generator options: 
    Level spawn location: World: (-172,64,295), Chunk: (at 4,4,7 in -11,18; contains blocks -176,0,288 to -161,255,303), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
    Level time: 124404153 game time, 128861290 day time
    Level dimension: 0
    Level storage version: 0x04ABD - Anvil
    Level weather: Rain time: 60178 (now: false), thunder time: 29363 (now: false)
    Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
    at net.minecraft.server.MinecraftServer.D(SourceFile:634)
    at lh.D(SourceFile:335)
    at net.minecraft.server.MinecraftServer.C(SourceFile:562)
    at net.minecraft.server.MinecraftServer.run(SourceFile:466)
    at java.lang.Thread.run(Thread.java:745)

-- System Details --
Details:
    Minecraft Version: 1.11.1
    Operating System: Linux (amd64) version 3.16.0-4-amd64
    Java Version: 1.7.0_111, Oracle Corporation
    Java VM Version: OpenJDK 64-Bit Server VM (mixed mode), Oracle Corporation
    Memory: 773155432 bytes (737 MB) / 1029701632 bytes (982 MB) up to 1029701632 bytes (982 MB)
    JVM Flags: 2 total; -Xmx1024M -Xms1024M
    IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
    Profiler Position: N/A (disabled)
    Player Count: 0 / 20; []
    Is Modded: Unknown (can't tell)
    Type: Dedicated Server (map_server.txt)