My server crashes and I can't join afterwards

Hey guys,
first of all an important information: I have NO idea about all that bukkit server things. I just wanted to play my modpack in singleplayer with a plugin. 2 hours ago I didn't even know this was a thing.

I am using Minecraft version 1.7.10 with the modpack "FTB Infinity Evolved".

After walking around for about 1 minute, i'll get kicked. I cant join the server afterwards (I will get kicked again).
I restarted the game and the server several times, but it did not help. I also created a new server.
My usual procedure: I'll run the "run.bat" file and wait till the server is up. Then I'll select "Mulitplayer" and connect with "localhost".

The error message is the following:

Code:

[I][22:34:12 WARN]: Failed to handle packet for /127.0.0.1:65054
org.bukkit.plugin.messaging.ChannelNameTooLongException: Attempted to send a Plugin Message to a channel that was too large. The maximum length a channel may be is 16 chars (attempted 20 - 'ImmersiveEngineering.
        at org.bukkit.plugin.messaging.StandardMessenger.validateChannel(StandardMessenger.java:438) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.2-20-g0b2ed13-b3108jnks]
        at org.bukkit.plugin.messaging.StandardMessenger.dispatchIncomingMessage(StandardMessenger.java:419) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.2-20-g0b2ed13-b3108jnks]
        at net.minecraft.server.v1_7_R4.PlayerConnection.a(PlayerConnection.java:1838) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.2-20-g0b2ed13-b3108jnks]
        at net.minecraft.server.v1_7_R4.PacketPlayInCustomPayload.a(PacketPlayInCustomPayload.java:31) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.2-20-g0b2ed13-b3108jnks]
        at net.minecraft.server.v1_7_R4.PacketPlayInCustomPayload.handle(PacketPlayInCustomPayload.java:43) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.2-20-g0b2ed13-b3108jnks]
        at net.minecraft.server.v1_7_R4.NetworkManager.a(NetworkManager.java:157) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.2-20-g0b2ed13-b3108jnks]
        at net.minecraft.server.v1_7_R4.ServerConnection.c(SourceFile:134) [craftbukkit.jar:git-Bukkit-1.7.9-R0.2-20-g0b2ed13-b3108jnks]
        at net.minecraft.server.v1_7_R4.MinecraftServer.v(MinecraftServer.java:667) [craftbukkit.jar:git-Bukkit-1.7.9-R0.2-20-g0b2ed13-b3108jnks]
        at net.minecraft.server.v1_7_R4.DedicatedServer.v(DedicatedServer.java:258) [craftbukkit.jar:git-Bukkit-1.7.9-R0.2-20-g0b2ed13-b3108jnks]
        at net.minecraft.server.v1_7_R4.MinecraftServer.u(MinecraftServer.java:558) [craftbukkit.jar:git-Bukkit-1.7.9-R0.2-20-g0b2ed13-b3108jnks]
        at net.minecraft.server.v1_7_R4.MinecraftServer.run(MinecraftServer.java:469) [craftbukkit.jar:git-Bukkit-1.7.9-R0.2-20-g0b2ed13-b3108jnks]
        at net.minecraft.server.v1_7_R4.ThreadServerApplication.run(SourceFile:628) [craftbukkit.jar:git-Bukkit-1.7.9-R0.2-20-g0b2ed13-b3108jnks]
[22:34:12 INFO]: Spedex_HD lost connection: Internal server error
[22:34:12 INFO]: Spedex_HD left the game.[/I]

I tried searching for something online, but didn't find any solution.
"ImmersiveEngineering" is a modpack from FTB Infinity Evolved.

The plugin I am using is the "sethome" plugin.
Can somebody help me with this issue?
Greetings
Spedex