AlchemyError1

[SEVERE] Could not load plugins\Alchemy.jar in plugins: null
org.bukkit.plugin.InvalidPluginException
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:113)
    at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:159)
    at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:107)
    at org.bukkit.craftbukkit.CraftServer.loadPlugins(CraftServer.java:61)
    at net.minecraft.server.MinecraftServer.e(MinecraftServer.java:204)
    at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:191)
    at net.minecraft.server.MinecraftServer.d(MinecraftServer.java:131)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:246)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:366)
Caused by: java.lang.NoSuchMethodException: ca.ziddia.alchemy.Alchemy.<init>()
    at java.lang.Class.getConstructor0(Unknown Source)
    at java.lang.Class.getConstructor(Unknown Source)
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:108)
    ... 8 more