kongr45gpen

Confirmed, here's the server output with the backtrace:

[Server thread/ERROR]: Couldn't set beacon
java.lang.IndexOutOfBoundsException
        at io.netty.buffer.EmptyByteBuf.readInt(EmptyByteBuf.java:470) ~[minecraft_server.14w32a.jar:?]
        at hb.readInt(SourceFile:639) ~[minecraft_server.14w32a.jar:?]
        at rg.a(SourceFile:1051) [minecraft_server.14w32a.jar:?]
        at ma.a(SourceFile:55) [minecraft_server.14w32a.jar:?]
        at ma.a(SourceFile:8) [minecraft_server.14w32a.jar:?]
        at ie.run(SourceFile:13) [minecraft_server.14w32a.jar:?]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [?:1.7.0_55]
        at java.util.concurrent.FutureTask.run(FutureTask.java:262) [?:1.7.0_55]
        at net.minecraft.server.MinecraftServer.y(SourceFile:575) [minecraft_server.14w32a.jar:?]
        at pl.y(SourceFile:305) [minecraft_server.14w32a.jar:?]
        at net.minecraft.server.MinecraftServer.x(SourceFile:530) [minecraft_server.14w32a.jar:?]
        at net.minecraft.server.MinecraftServer.run(SourceFile:446) [minecraft_server.14w32a.jar:?]
        at java.lang.Thread.run(Thread.java:744) [?:1.7.0_55]

@unknown, which Java version are you using? Try switching to 1.6 and see if you can reproduce it.

Mog, which Java version are you using? This only seems to be an 1.6 issue _{(redstonebuilder confirmed he has Java 1.6)}

Can't confirm on 64 bit Kubuntu 14.04 (Java 1.7.0_55 with an AMD HD5670).