Bukkit

I have put up 5 Recent signs but when they try to update the console outputs this error:

13:43:15 [SEVERE] Could not pass event SIGN_CHANGE to WebAuction
java.lang.NullPointerException
        at me.exote.webauction.listeners.WebAuctionBlockListener.onSignChange(WebAuctionBlockListener.java:82)
        at org.bukkit.plugin.java.JavaPluginLoader$36.execute(JavaPluginLoader.java:511)
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:58)
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:339)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:1068)
        at net.minecraft.server.Packet130UpdateSign.a(SourceFile:41)
        at net.minecraft.server.NetworkManager.b(NetworkManager.java:226)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:93)
        at org.getspout.spout.SpoutNetServerHandler.a(SpoutNetServerHandler.java:550)
        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)

The signs are made exactly after the tutorial, i.e. first line says only "[WebAuction]", second line says only "Recent" and the third contains a single number from 1 to 5.
I got the "Recent auction sign created" message in the chat for each sign.

Webauction works fine otherwise.

It seems that either it has found an auction with no price, or the economy plugin is interacting strangely.

Are you running in single or multithread mode (in the plugin config)?

Please have a check of your database to see if there is anything odd in there, in particular the auctions table.

@Exote: Go

Multithread is off. And as far as I can see there's nothing wrong with the tables, except that the Recent sign table is empty.

Oh and I don't have an economy plugin currently.

It has appeared to work fine without one so far...