Console error setrank

org.bukkit.command.CommandExeption: Unhandled exeption executing command 'prom
o' in plugin SetRankPB v1.2.1
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:42)
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:16
6)
        at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:3
78)
        at net.minecraft.server.NetServerHandler.handleCommand(NetServerHandler.
java:758)
        at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:723)

        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:716)
        at net.minecraft.server.Packet3Chat.a(Packet3Chat.java:33)
        at net.minecraft.server.NetworkManager.b(NetworkManager.java:226)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:93)
        at net.minecraft.server.NetworkListenThread.a(SourceFile:108)
        at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:527)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:425)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:457)
Caused by: java.lang.ClassCastException: java.lang.Integer cannot be cast to jav
a.lang.Double
        at com.baummann.setrankpb.commands.CommandPromotion.onCommand(CommandPro
motion.java:66)
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:40)
        ... 12 more
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