Owen

Hi, thanks for the reply, unfortunately, I don't fully understand how to install java 7 on my Linux centOS, I would really appreciate it if you could send a tutorial or something my way. :-\

I've got this same problem. Please note, I'm running this on linux. Aliasing material 47 name: bookshelf Aliasing material 48 name: stoneMoss Aliasing material 49 name: obsidian Aliasing material 50 name: torch Aliasing material 51 name: fire java.lang.UnsupportedClassVersionError: net/minecraft/server/TileEntityMobSpawner : Unsupported major.minor version 51.0 at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:634) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader.defineClass(URLClassLoader.java:277) at java.net.URLClassLoader.access$000(URLClassLoader.java:73) at java.net.URLClassLoader$1.run(URLClassLoader.java:212) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:205) at java.lang.ClassLoader.loadClass(ClassLoader.java:321) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294) at java.lang.ClassLoader.loadClass(ClassLoader.java:266) at net.minecraft.server.Block.<clinit>(Block.java:79) at net.minecraft.server.StatisticList.a(SourceFile:117) at net.minecraft.server.StatisticList.<clinit>(SourceFile:52) at net.minecraft.server.MinecraftServer.main(MinecraftServer.java:589) at org.bukkit.craftbukkit.Main.main(Main.java:134)