NullPointer on File properties

Hello,
I'm working on a shop plugin and want to create for every player an own file, in which I can store prices, but every time I call the method getPlayerPrice there's a NullPointer on the prop, but I don't know how to fix it.
And on loadProperties it never find's a file, except in the beginning when its the globalPricesFile...

Code:java

public static DynamicShop plugin;
    private static Properties prop = new Properties();
    static File globalPricesFile;
 
    public FileManager(DynamicShop instance){
        plugin = instance;
        globalPricesFile = new File(plugin.getDataFolder() + File.separator + "GlobalPrices.cfg");
    }
 
    public static void saveProperties(File file) {
    try {
        FileOutputStream fileWriter = new FileOutputStream(file);
        prop.store(fileWriter, "Be careful when manually editing this file!");
        fileWriter.flush();
        fileWriter.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
 
    public static void loadProperties(File file) {
        try {
                FileInputStream fileReader = new FileInputStream(file);
                prop.load(fileReader);
                fileReader.close();}
            catch (FileNotFoundException e) {
                saveProperties(file);
                //loadProperties(file);
                }
            catch (IOException e) {
                e.printStackTrace();}
    }public static Double getPlayerPrice(Player player, String material){
        prop = new Properties();
        File playerFile = new File(plugin.getDataFolder() + File.separator + "Prices" + player.getName() + ".cfg");
        System.out.println(plugin.name + "file: " + playerFile.toString() + "prop: " + prop.toString());
        loadProperties(playerFile);
        Double price = Double.parseDouble(prop.getProperty(material.toUpperCase(Locale.ENGLISH)));
        return price;
    }
 
    public static void setPlayerPrice(Player player, String material, Double price) {
        prop = new Properties();
        File playerFile = new File(plugin.getDataFolder() + File.separator + "Prices" + player.getName() + ".cfg");
 
        loadProperties(playerFile);
 
        prop.setProperty(material.toUpperCase(Locale.ENGLISH), price.toString());
        saveProperties(playerFile);
    }

NullPointer:

Code:

2011-10-23 19:23:59 [SEVERE] Could not pass event PLAYER_INTERACT to Dynamic Shop
java.lang.NullPointerException
    at sun.misc.FloatingDecimal.readJavaFormatString(Unknown Source)
    at java.lang.Double.parseDouble(Unknown Source)
    at me.gerry.dynamicshop.FileManager.getPlayerPrice(FileManager.java:68)
    at me.gerry.dynamicshop.DynamicShopPlayerListener.onPlayerInteract(DynamicShopPlayerListener.java:97)
    at org.bukkit.plugin.java.JavaPluginLoader$11.execute(JavaPluginLoader.java:330)
    at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:58)
    at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:339)
    at org.bukkit.craftbukkit.event.CraftEventFactory.callPlayerInteractEvent(CraftEventFactory.java:171)
    at net.minecraft.server.ItemInWorldManager.interact(ItemInWorldManager.java:265)
    at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:592)
    at net.minecraft.server.Packet15Place.a(SourceFile:57)
    at net.minecraft.server.NetworkManager.b(NetworkManager.java:226)
    at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:92)
    at net.minecraft.server.NetworkListenThread.a(SourceFile:108)
    at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:471)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:374)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:417)

 

Paste the null pointer exception

 

Also, try putting your code between

Code:

[syntax=java]
Code Here
[/syntax]

Makes it a lot easier to read.