Can't Download Plugins to Bukkit Server..

This happens but its a different error for each plugin

Last login: Wed Jul 2 16:48:05 on ttys000
/Users/*******/Desktop/CraftBukkit/start_server.command ; exit;
********** iMac:~ **********$ /Users/r*******l/Desktop/CraftBukkit/start_server.command ; exit;
16:49:17 [INFO] Starting minecraft server version 1.7.9
16:49:17 [INFO] Loading properties
16:49:17 [INFO] Default game type: SURVIVAL
16:49:17 [INFO] Generating keypair
16:49:18 [INFO] Starting Minecraft server on *:25565
16:49:18 [INFO] This server is running CraftBukkit version git-Bukkit-1.6.4-R2.0-b2918jnks (MC: 1.6.4) (Implementing API version 1.6.4-R2.0)
16:49:18 [WARNING] Failed to load white-list: java.io.FileNotFoundException: ./white-list.txt (No such file or directory)
16:49:18 [INFO] Preparing level "world"
16:49:18 [INFO] Preparing start region for level 0 (Seed: 2627190388772420647)
16:49:19 [INFO] Preparing spawn area: 12%
16:49:20 [INFO] Preparing spawn area: 32%
16:49:21 [INFO] Preparing spawn area: 47%
16:49:22 [INFO] Preparing spawn area: 64%
16:49:23 [INFO] Preparing spawn area: 78%
16:49:24 [INFO] Preparing start region for level 1 (Seed: 2627190388772420647)
16:49:25 [INFO] Preparing spawn area: 17%
16:49:26 [INFO] Preparing spawn area: 37%
16:49:27 [INFO] Preparing spawn area: 48%
16:49:28 [INFO] Preparing spawn area: 63%
16:49:29 [INFO] Preparing spawn area: 88%
16:49:30 [INFO] Preparing start region for level 2 (Seed: 2627190388772420647)
16:49:31 [INFO] Preparing spawn area: 65%
16:49:31 [INFO] Done (13.532s)! For help, type "help" or "?"
>reload
16:50:08 [SEVERE] Could not load 'plugins/BloodParticles.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: me/CosmicReaperMC/BloodParticles/BloodBase : Unsupported major.minor version 51.0
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:184)
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305)
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230)
at org.bukkit.craftbukkit.v1_6_R3.CraftServer.loadPlugins(CraftServer.java:241)
at org.bukkit.craftbukkit.v1_6_R3.CraftServer.reload(CraftServer.java:613)
at org.bukkit.Bukkit.reload(Bukkit.java:277)
at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:23)
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:192)
at org.bukkit.craftbukkit.v1_6_R3.CraftServer.dispatchCommand(CraftServer.java:528)
at org.bukkit.craftbukkit.v1_6_R3.CraftServer.dispatchServerCommand(CraftServer.java:515)
at net.minecraft.server.v1_6_R3.DedicatedServer.as(DedicatedServer.java:263)
at net.minecraft.server.v1_6_R3.DedicatedServer.t(DedicatedServer.java:228)
at net.minecraft.server.v1_6_R3.MinecraftServer.s(MinecraftServer.java:488)
at net.minecraft.server.v1_6_R3.MinecraftServer.run(MinecraftServer.java:421)
at net.minecraft.server.v1_6_R3.ThreadServerApplication.run(SourceFile:583)
Caused by: java.lang.UnsupportedClassVersionError: me/CosmicReaperMC/BloodParticles/BloodBase : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:637)
at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
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.findClass0(PluginClassLoader.java:80)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)
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:249)
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:173)
... 14 more
16:50:08 [INFO] Server permissions file permissions.yml is empty, ignoring it
16:50:08 [INFO] CONSOLE: Reload complete.
>