Random Map explosions when starting server

Code:

java.lang.NullPointerException
        at net.minecraft.server.Explosion.<init>(Explosion.java:47)
        at net.minecraft.server.World.a(SourceFile:1300)
        at net.minecraft.server.WorldServer.a(WorldServer.java:99)
        at net.minecraft.server.World.a(SourceFile:1296)
        at net.minecraft.server.EntityTNTPrimed.d(EntityTNTPrimed.java:70)
        at net.minecraft.server.EntityTNTPrimed.b_(EntityTNTPrimed.java:61)
        at net.minecraft.server.World.a(SourceFile:1116)
        at net.minecraft.server.WorldServer.a(WorldServer.java:41)
        at net.minecraft.server.World.f(SourceFile:1092)
        at net.minecraft.server.World.c(SourceFile:1071)
        at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:260)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:197)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:512)
2011-01-23 09:53:52 [SEVERE] Unexpected exception
java.lang.NullPointerException
        at net.minecraft.server.Explosion.<init>(Explosion.java:47)
        at net.minecraft.server.World.a(SourceFile:1300)
        at net.minecraft.server.WorldServer.a(WorldServer.java:99)
        at net.minecraft.server.World.a(SourceFile:1296)
        at net.minecraft.server.EntityTNTPrimed.d(EntityTNTPrimed.java:70)
        at net.minecraft.server.EntityTNTPrimed.b_(EntityTNTPrimed.java:61)
        at net.minecraft.server.World.a(SourceFile:1116)
        at net.minecraft.server.WorldServer.a(WorldServer.java:41)
        at net.minecraft.server.World.f(SourceFile:1092)
        at net.minecraft.server.World.c(SourceFile:1071)
        at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:260)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:197)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:512)

Im now recieving Errors of an Explosion on my map when i start it up. Not sure whats going on.