Severe Error, yet shops seem to work fine (so far?)

I believe all of my shops are up and running before this error appears.

2011-03-26 15:47:30 [SEVERE] null loading LocalShops v1.15b (Is it up to date?)
java.lang.NullPointerException
at java.util.Arrays.mergeSort(Arrays.java:1157)
at java.util.Arrays.mergeSort(Arrays.java:1168)
at java.util.Arrays.sort(Arrays.java:1092)
at java.util.Collections.sort(Collections.java:134)
at net.centerleft.localshops.Shop.getItems(Shop.java:248)
at net.centerleft.localshops.ShopData.saveShop(ShopData.java:315)
at net.centerleft.localshops.ShopData.LoadShops(ShopData.java:272)
at net.centerleft.localshops.LocalShops.onEnable(LocalShops.java:130)
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:118)
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:467)
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:217)
at org.bukkit.craftbukkit.CraftServer.loadPlugin(CraftServer.java:92)
at org.bukkit.craftbukkit.CraftServer.loadPlugins(CraftServer.java:70)
at net.minecraft.server.MinecraftServer.e(MinecraftServer.java:203)
at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:190)
at net.minecraft.server.MinecraftServer.d(MinecraftServer.java:130)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:245)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:366)