Bukkit

The plugin crashes when loading the server and reloading the server but not as much when start it fresh.
I have CraftBukkit 1.3.1 R2.0 running DynamicEconomy 0.92

05:02:03 [WARNING] Task of 'DynamicEconomy' generated an exception
java.lang.NumberFormatException: For input string: "?"
        at sun.misc.FloatingDecimal.readJavaFormatString(Unknown Source)
        at java.lang.Double.valueOf(Unknown Source)
        at me.ksafin.DynamicEconomy.EnderEngine.calcPrice(EnderEngine.java:220)
        at me.ksafin.DynamicEconomy.EnderEngine.incrementStock(EnderEngine.java:
136)
        at me.ksafin.DynamicEconomy.RandomEvent.run(RandomEvent.java:80)
        at org.bukkit.craftbukkit.scheduler.CraftScheduler.mainThreadHeartbeat(C
raftScheduler.java:126)
        at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:510)
        at net.minecraft.server.DedicatedServer.q(DedicatedServer.java:212)
        at net.minecraft.server.MinecraftServer.p(MinecraftServer.java:474)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:406)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:539)

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