having trouble running mcMMO in my craftbukkit server.. pls help!!

Every time i try and run my server this error comes up..... HOW DO I FIX IT ?
[18:26:22 INFO]: [mcMMO] Loading mcMMO v1.5.03-SNAPSHOT-b46

[18:26:22 INFO]: [mcMMO] Enabling mcMMO v1.5.03-SNAPSHOT-b46

[18:26:23 ERROR]: [mcMMO] There was an error while enabling mcMMO!

[18:26:23 WARN]: java.lang.UnsupportedClassVersionError: com/gmail/nossr50/metrics/mcstats/Metrics$Plotter : Unsupported major.minor version 51.0

[18:26:23 WARN]: at java.lang.ClassLoader.defineClass1(Native Method)

[18:26:23 WARN]: at java.lang.ClassLoader.defineClassCond(ClassLoader.java:637)

[18:26:23 WARN]: at java.lang.ClassLoader.defineClass(ClassLoader.java:621)

[18:26:23 WARN]: at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)

[18:26:23 WARN]: at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)

[18:26:23 WARN]: at java.net.URLClassLoader.access$000(URLClassLoader.java:58)

[18:26:23 WARN]: at java.net.URLClassLoader$1.run(URLClassLoader.java:197)

[18:26:23 WARN]: at java.security.AccessController.doPrivileged(Native Method)

[18:26:23 WARN]: at java.net.URLClassLoader.findClass(URLClassLoader.java:190)

[18:26:23 WARN]: at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:101)

[18:26:23 WARN]: at org.bukkit.plugin.java.JavaPluginLoader.getClassByName(JavaPluginLoader.java:193)

[18:26:23 WARN]: at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:97)

[18:26:23 WARN]: at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:86)

[18:26:23 WARN]: at java.lang.ClassLoader.loadClass(ClassLoader.java:306)

[18:26:23 WARN]: at java.lang.ClassLoader.loadClass(ClassLoader.java:247)

[18:26:23 WARN]: at com.gmail.nossr50.mcMMnEnable(mcMMO.java:184)

[18:26:23 WARN]: at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:316)

[18:26:23 WARN]: at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:332)

[18:26:23 WARN]: at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:412)

[18:26:23 WARN]: at org.bukkit.craftbukkit.v1_7_R4.CraftServer.loadPlugin(CraftServer.java:476)

[18:26:23 WARN]: at org.bukkit.craftbukkit.v1_7_R4.CraftServer.enablePlugins(CraftServer.java:394)

[18:26:23 WARN]: at net.minecraft.server.v1_7_R4.DedicatedServer.init(DedicatedServer.java:153)

[18:26:23 WARN]: at net.minecraft.server.v1_7_R4.MinecraftServer.run(MinecraftServer.java:458)

[18:26:23 WARN]: at net.minecraft.server.v1_7_R4.ThreadServerApplication.run(SourceFile:628)

[18:26:23 INFO]: [mcMMO] Disabling mcMMO v1.5.03-SNAPSHOT-b46

 

i have java 7 update 51.0 and it still doesn't work?

 

oh thanks heaps! how do i do that though haha sorry I'm new to this server stuff?

 

by the way i am on mac not windows