Error

[13:40:56] [Server thread/INFO]: Starting minecraft server version 1.7.2
[13:40:56] [Server thread/INFO]: Loading properties
[13:40:56] [Server thread/INFO]: Default game type: SURVIVAL
[13:40:56] [Server thread/INFO]: Generating keypair
[13:40:56] [Server thread/INFO]: Starting Minecraft server on *:25565
[13:40:56] [Server thread/INFO]: This server is running CraftBukkit version git-Bukkit-1.7.2-R0.3-b3020jnks (MC: 1.7.2) (Implementing API version 1.7.2-R0.3)
[13:40:56] [Server thread/ERROR]: Could not load 'plugins\MyFirstPlugin.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: Cannot find main class `me.ZygoZ.MyFirstPlugin'
	at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:42) ~[craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:133) ~[craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:313) ~[craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:236) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at org.bukkit.craftbukkit.v1_7_R1.CraftServer.loadPlugins(CraftServer.java:350) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at org.bukkit.craftbukkit.v1_7_R1.CraftServer.<init>(CraftServer.java:312) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at net.minecraft.server.v1_7_R1.PlayerList.<init>(PlayerList.java:63) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at net.minecraft.server.v1_7_R1.DedicatedPlayerList.<init>(SourceFile:14) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at net.minecraft.server.v1_7_R1.DedicatedServer.init(DedicatedServer.java:126) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:424) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
Caused by: java.lang.ClassNotFoundException: me.ZygoZ.MyFirstPlugin
	at java.net.URLClassLoader$1.run(Unknown Source) ~[?:1.7.0_21]
	at java.net.URLClassLoader$1.run(Unknown Source) ~[?:1.7.0_21]
	at java.security.AccessController.doPrivileged(Native Method) ~[?:1.7.0_21]
	at java.net.URLClassLoader.findClass(Unknown Source) ~[?:1.7.0_21]
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:77) ~[craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:62) ~[craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.7.0_21]
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.7.0_21]
	at java.lang.Class.forName0(Native Method) ~[?:1.7.0_21]
	at java.lang.Class.forName(Unknown Source) ~[?:1.7.0_21]
	at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:40) ~[craftbukkit.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
	... 10 more
[13:40:56] [Server thread/INFO]: Preparing level "world"
[13:40:57] [Server thread/INFO]: Preparing start region for level 0 (Seed: 4975015460920999623)
[13:40:57] [Thread-7/INFO]: ----- Bukkit Auto Updater -----
[13:40:57] [Thread-7/INFO]: It appears that you're running a Beta Build, when you've specified in bukkit.yml that you prefer to run Recommended Builds.
[13:40:57] [Thread-7/INFO]: If you would like to be kept informed about new Beta Build releases, it is recommended that you change 'preferred-channel' in your bukkit.yml to 'beta'.
[13:40:57] [Thread-7/INFO]: With that set, you will be told whenever a new version is available for download, so that you can always keep up to date and secure with the latest fixes.
[13:40:57] [Thread-7/INFO]: If you would like to disable this warning, simply set 'suggest-channels' to false in bukkit.yml.
[13:40:57] [Thread-7/INFO]: ----- ------------------- -----
[13:40:58] [Server thread/INFO]: Preparing spawn area: 52%
[13:40:58] [Server thread/INFO]: Preparing start region for level 1 (Seed: 4975015460920999623)
[13:40:59] [Server thread/INFO]: Preparing spawn area: 64%
[13:41:00] [Server thread/INFO]: Preparing start region for level 2 (Seed: 4975015460920999623)
[13:41:00] [Server thread/INFO]: Server permissions file permissions.yml is empty, ignoring it
[13:41:00] [Server thread/INFO]: Done (3,495s)! For help, type "help" or "?"