If you are okay with loosing your wirelessredstone stuff, you could try disabling wirelessredstone temporarily and see if it fixes it. The error seems to be coming from that.
Edit: Are you sure it is exactly the same error? Could you post it anyway.
[SEVERE] Encountered an unexpected exception NullPointerException
java.lang.NullPointerException
at codechicken.wirelessredstone.core.RedstoneEtherServer.setDimensionTransmitterCount(RedstoneEtherServer.java:636)
at codechicken.wirelessredstone.core.SaveManager.loadDimensionHash(SaveManager.java:672)
at codechicken.wirelessredstone.core.RedstoneEtherServer.<init>(RedstoneEtherServer.java:34)
at codechicken.wirelessredstone.core.RedstoneEther.loadServerWorld(RedstoneEther.java:120)
at codechicken.wirelessredstone.core.WRCoreEventHandler.onWorldLoad(WRCoreEventHandler.java:30)
at net.minecraftforge.event.ASMEventHandler_93_WRCoreEventHandler_onWorldLoad_Load.invoke(.dynamic)
at net.minecraftforge.event.ASMEventHandler.invoke(ASMEventHandler.java:35)
at net.minecraftforge.event.EventBus.post(EventBus.java:103)
at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:279)
at ho.c(DedicatedServer.java:180)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:458)
at fy.run(SourceFile:849)
[SEVERE] This crash report has been saved to: C:\Users\Gaege\Desktop\Mindcrack server\.\crash-reports\crash-2013-04-29_12.00.40-server.txt
Thats what i get each time in my server log and how would i disable just wireless red stone on the server?