2013-03-02 14:30:07 [INFO] 210 recipes
2013-03-02 14:30:07 [SEVERE] Could not load 'plugins/HeroicDeath.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.NoClassDefFoundError: org/bukkit/event/entity/EntityListener
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:182)
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305)
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230)
at org.bukkit.craftbukkit.v1_4_R1.CraftServer.loadPlugins(CraftServer.java:239)
at org.bukkit.craftbukkit.v1_4_R1.CraftServer.reload(CraftServer.java:594)
at org.bukkit.Bukkit.reload(Bukkit.java:184)
at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:23)
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:186)
at org.bukkit.craftbukkit.v1_4_R1.CraftServer.dispatchCommand(CraftServer.java:514)
at org.bukkit.craftbukkit.v1_4_R1.CraftServer.dispatchServerCommand(CraftServer.java:506)
at net.minecraft.server.v1_4_R1.DedicatedServer.al(DedicatedServer.java:260)
at net.minecraft.server.v1_4_R1.DedicatedServer.r(DedicatedServer.java:225)
at net.minecraft.server.v1_4_R1.MinecraftServer.q(MinecraftServer.java:494)
at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:427)
at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849)
Caused by: java.lang.NoClassDefFoundError: org/bukkit/event/entity/EntityListener
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
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(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at com.herocraftonline.squallseed31.heroicdeath.HeroicDeath.(HeroicDeath.java:26)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:178)
... 14 more
Caused by: java.lang.ClassNotFoundException: org.bukkit.event.entity.EntityListener
at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:70)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 33 more
2013-03-02 14:30:08 [SEVERE] Could not load 'plugins/VoxelSniper.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.NoClassDefFoundError: net/minecraft/server/Entity
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:182)
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305)
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230)
at org.bukkit.craftbukkit.v1_4_R1.CraftServer.loadPlugins(CraftServer.java:239)
at org.bukkit.craftbukkit.v1_4_R1.CraftServer.reload(CraftServer.java:594)
at org.bukkit.Bukkit.reload(Bukkit.java:184)
at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:23)
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:186)
at org.bukkit.craftbukkit.v1_4_R1.CraftServer.dispatchCommand(CraftServer.java:514)
at org.bukkit.craftbukkit.v1_4_R1.CraftServer.dispatchServerCommand(CraftServer.java:506)
at net.minecraft.server.v1_4_R1.DedicatedServer.al(DedicatedServer.java:260)
at net.minecraft.server.v1_4_R1.DedicatedServer.r(DedicatedServer.java:225)
at net.minecraft.server.v1_4_R1.MinecraftServer.q(MinecraftServer.java:494)
at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:427)
at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849)
Caused by: java.lang.NoClassDefFoundError: net/minecraft/server/Entity
at com.thevoxelbox.voxelsniper.VoxelSniper.(VoxelSniper.java:49)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:178)
... 14 more
Caused by: java.lang.ClassNotFoundException: net.minecraft.server.Entity
at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:70)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 20 more

Since other plugins on your server are not loading as well, I would say
it's not an issue with sniper. Check if you are using the latest/correct
Bukkit version.

ok thanx