Server Crashes When I Enter A Mystcraft Age

[lordgaspode]

Hi, |I recently setup a server to run the Direwolf20 server modpack, and it's been cool, but today I created a Mystcraft age, and when ever I try to enter the age, the server crashes.
I have posted the errors that appear in the server window below.
Could someone please explain what it means and if there is any possible fix, as I'm a complete noob when it comes to servers.

2013-01-12 10:25:14 [SEVERE] [Minecraft] Encountered an unexpected exception NoClassDefFoundErrorjava.lang.NoClassDefFoundError: lat a.<init>(CrashReport.java:27)
at a.a(CrashReport.java:319)
at yc.a(World.java:412)
at com.eloraam.redpower.world.WorldGenMarble.a(WorldGenMarble.java:60)
at com.eloraam.redpower.world.WorldGenHandler.generate(WorldGenHandler.java:117)
at cpw.mods.fml.common.registry.GameRegistry.generateWorld(GameRegistry.java:90)
at im.a(ChunkProviderServer.java:259)
at zz.a(Chunk.java:1258)
at im.c(ChunkProviderServer.java:153)
at il.<init>(PlayerInstance.java:35)
at ik.a(SourceFile:172)
at ik.a(SourceFile:203)
at gm.a(ServerConfigurationManager.java:163)
at gm.c(ServerConfigurationManager.java:206)
at gm.a(ServerConfigurationManager.java:123)
at it.completeConnection(NetLoginHandler.java:195)
at cpw.mods.fml.common.network.FMLNetworkHandler.handleClientConnection(FMLNetworkHandler.java:153)
at cpw.mods.fml.common.network.FMLNetworkHandler.onConnectionReceivedFromClient(FMLNetworkHandler.java:107)
at it.d(NetLoginHandler.java:179)
at it.c(NetLoginHandler.java:72)
at hu.a(ServerListenThread.java:56)
at ht.b(SourceFile:29)
at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:702)
at ho.r(DedicatedServer.java:270)
at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:598)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:497)

 

[Nessiroj]

Is it only this age that crashes it or with all newly created onces? It often happens dat ages are instable and crashes the server or client.

 

[lordgaspode]

Well I am unable to access anything now as when I restart the server, it tries to spawn me in the new age (the only one I created) and crashes the server with the same error messages. I am unable to spawn at all to create new ages or even to return to the overworld.

 

[Nessiroj]

delete <yourname>.dat file in your world folder, afterwards you should spawn on the normal world spawn only you will lose your whole inventory.
or use an external program to change it (whouldn't recommend it if you don't know how).

 

[lordgaspode]

Thanks for that, you helped me out a bunch, I'll just avoid using Mystcraft for a while i think

 

[Nessiroj]

no need to avoid it, just create a new age now you have nothing in your inventory. You will see it will work. It's just some ages that become instanly corrupt when created

 

[Hello1423]

I am having the same problem, will this fix destroy my thaumcraft researches as well as my inventory?