Crash Spigot Crashes after Error

I just installed the latest build of Spigot (#735) and the console starts to get an error after a short amount of time, then crash the server.

Code (Text):

9:56:56 PM CONSOLE: [SEVERE] net.minecraft.server.v1_5_R2.ExceptionWorldConflict: The save is being accessed from another location, aborting
9:56:56 PM CONSOLE: [SEVERE] at net.minecraft.server.v1_5_R2.WorldNBTStorage.checkSession(WorldNBTStorage.java:69)
9:56:56 PM CONSOLE: [SEVERE] at net.minecraft.server.v1_5_R2.World.E(World.java:2715)
9:56:56 PM CONSOLE: [SEVERE] at net.minecraft.server.v1_5_R2.ChunkRegionLoader.a(ChunkRegionLoader.java:118)
9:56:56 PM CONSOLE: [SEVERE] at net.minecraft.server.v1_5_R2.ChunkProviderServer.saveChunk(ChunkProviderServer.java:209)
9:56:56 PM CONSOLE: [SEVERE] at net.minecraft.server.v1_5_R2.ChunkProviderServer.unloadChunks(ChunkProviderServer.java:299)
9:56:56 PM CONSOLE: [SEVERE] at net.minecraft.server.v1_5_R2.WorldServer.doTick(WorldServer.java:179)
9:56:56 PM CONSOLE: [SEVERE] at net.minecraft.server.v1_5_R2.MinecraftServer.r(MinecraftServer.java:551)
9:56:56 PM CONSOLE: [SEVERE] at net.minecraft.server.v1_5_R2.DedicatedServer.r(DedicatedServer.java:229)
9:56:56 PM CONSOLE: [SEVERE] at net.minecraft.server.v1_5_R2.MinecraftServer.q(MinecraftServer.java:469)
9:56:56 PM CONSOLE: [SEVERE] at net.minecraft.server.v1_5_R2.MinecraftServer.run(MinecraftServer.java:401)
9:56:56 PM CONSOLE: [SEVERE] at net.minecraft.server.v1_5_R2.ThreadServerApplication.run(SourceFile:573)

Any help would be appreciated.