citizens problem

22:42:28 [WARNING] [Citizens] Task #42 for Citizens v2.0.8-SNAPSHOT (build 782)
generated an exception
java.lang.IllegalArgumentException: Cannot set to an empty path
        at org.apache.commons.lang.Validate.notEmpty(Validate.java:363)
        at org.bukkit.configuration.MemorySection.set(MemorySection.java:159)
        at org.bukkit.configuration.MemorySection.set(MemorySection.java:189)
        at net.citizensnpcs.api.util.YamlStorage$YamlKey.removeKey(YamlStorage.j
ava:233)
        at net.citizensnpcs.api.util.DataKey.transferOld(DataKey.java:39)
        at net.citizensnpcs.api.util.DataKey.createRelativeKey(DataKey.java:19)
        at net.citizensnpcs.api.util.YamlStorage$YamlKey.getRelative(YamlStorage
.java:189)
        at net.citizensnpcs.api.util.YamlStorage$YamlKey.getRelative(YamlStorage
.java:91)
        at net.citizensnpcs.npc.CitizensNPC$1.apply(CitizensNPC.java:101)
        at net.citizensnpcs.npc.CitizensNPC$1.apply(CitizensNPC.java:98)
        at com.google.common.collect.Iterators$8.next(Iterators.java:782)
        at com.google.common.collect.Iterators.addAll(Iterators.java:352)
        at com.google.common.collect.Iterables.addAll(Iterables.java:329)
        at net.citizensnpcs.npc.CitizensNPC.load(CitizensNPC.java:98)
        at net.citizensnpcs.api.npc.SimpleNPCDataStore.loadInto(SimpleNPCDataSto
re.java:36)
        at net.citizensnpcs.Citizens$1.run(Citizens.java:274)
        at org.bukkit.craftbukkit.v1_5_R2.scheduler.CraftTask.run(CraftTask.java
:53)
        at org.bukkit.craftbukkit.v1_5_R2.scheduler.CraftScheduler.mainThreadHea
rtbeat(CraftScheduler.java:344)
        at net.minecraft.server.v1_5_R2.MinecraftServer.r(MinecraftServer.java:5
10)
        at net.minecraft.server.v1_5_R2.DedicatedServer.r(DedicatedServer.java:2
25)
        at net.minecraft.server.v1_5_R2.MinecraftServer.q(MinecraftServer.java:4
74)
        at net.minecraft.server.v1_5_R2.MinecraftServer.run(MinecraftServer.java
:407)
        at net.minecraft.server.v1_5_R2.ThreadServerApplication.run(SourceFile:5
73)