Need help with PVPGun plugin

I've had this problem with my PVPGun plugin running on my sever.

16:17:14 [INFO] This server is running CraftBukkit version git-Bukkit-1.3.1-R2.0-b2340jnks (MC: 1.3.1) (Implementing API version 1.3.1-R2.0)
16:17:15 [INFO] While loading PVPGun (plugins/pvpgun.jar) found old-data folder: plugins/pvpgun next to the new one: plugins/PVPGun
16:17:15 [SEVERE] Could not load 'plugins/pvpgun.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: com/orange451/PVPGun/main : Unsupported major.minor version 51.0
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:155)
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305)
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230)
at org.bukkit.craftbukkit.CraftServer.loadPlugins(CraftServer.java:222)
at org.bukkit.craftbukkit.CraftServer.<init>(CraftServer.java:198)
at net.minecraft.server.ServerConfigurationManagerAbstract.<init>(ServerConfigurationManagerAbstract.java:50)
at net.minecraft.server.ServerConfigurationManager.<init>(SourceFile:11)
at net.minecraft.server.DedicatedServer.init(DedicatedServer.java:105)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:378)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:539)
Caused by: java.lang.UnsupportedClassVersionError: com/orange451/PVPGun/main : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:44)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:29)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:247)
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:144)
... 9 more
I can answer any questions about my sever.

 

I have this problem too. It gets fixed when you use the 1.2.5 version of the pl. But i dont know where to get it. If you find it please give me the link

http://host-a.net/u/orange451/PVPGun.jar this link fixed it. replace the jar but leave the gun folder in your plugins folder. It worked for me

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

That fixed it, If you go on the popgun forum theres a link on the I think 8th or 9th page in big red letters'