Bukkit

What steps will reproduce the problem?
1.
2.
3.

What is the expected output? What do you see instead?
When you place specific allowed blocks they should be erased after the game is over

Instead they remained there on the next game.

What version of the product are you using?
1.0.6

Do you have an error log of what happened?
net.minecraft.server.v1_7_R3.ExceptionWorldConflict: The save is being accessed from another location, aborting
[23:03:56] [Server thread/WARN]:     at net.minecraft.server.v1_7_R3.WorldNBTStorage.checkSession(WorldNBTStorage.java:72)
[23:03:56] [Server thread/WARN]:     at net.minecraft.server.v1_7_R3.World.G(World.java:2804)
[23:03:56] [Server thread/WARN]:     at net.minecraft.server.v1_7_R3.ChunkRegionLoader.a(ChunkRegionLoader.java:128)
[23:03:56] [Server thread/WARN]:     at net.minecraft.server.v1_7_R3.ChunkProviderServer.saveChunk(ChunkProviderServer.java:231)
[23:03:56] [Server thread/WARN]:     at net.minecraft.server.v1_7_R3.ChunkProviderServer.unloadChunks(ChunkProviderServer.java:325)
[23:03:56] [Server thread/WARN]:     at net.minecraft.server.v1_7_R3.WorldServer.doTick(WorldServer.java:196)
[23:03:56] [Server thread/WARN]:     at net.minecraft.server.v1_7_R3.MinecraftServer.v(MinecraftServer.java:672)
[23:03:56] [Server thread/WARN]:     at net.minecraft.server.v1_7_R3.DedicatedServer.v(DedicatedServer.java:283)
[23:03:56] [Server thread/WARN]:     at net.minecraft.server.v1_7_R3.MinecraftServer.u(MinecraftServer.java:576)
[23:03:56] [Server thread/WARN]:     at net.minecraft.server.v1_7_R3.MinecraftServer.run(MinecraftServer.java:482)
[23:03:56] [Server thread/WARN]:     at net.minecraft.server.v1_7_R3.ThreadServerApplication.run(SourceFile:628)

Please provide any additional information below.

I know why this is happening, it tries to replace the files before it is finished unloading them therefore the files are still in use and can't be replaced. Need to make a longer cool down between them.