Amadiro

For reference, should anybody else stumble upon this post: go into $TEKKIT_FOLDER/config/ and open ModLoader.txt change the line mod_EE=on to mod_EE=off This turns off Equivalent Exchange. start the server. This removes all EE items from the world shut down the server change back the line you've changed in ModLoader.txt to what it was originally, to turn EE back on. start the server back up To prevent the problem from occurring again, you can use http://forums.technicpack.net/index.php/topic,5663.0.html

After searching the forums some more, this appears to be a known bug. I'll post a solution here, once I've found one that is satisfactory (I'm hoping I can edit the world with MCEdit and fix the problem.)

Launcher/pack Version: 2.1.1 (Tekkit_Server_2.1.1.zip) Operating System: Linux 2.6.18-308.1.1.el5 #1 SMP, x86_64 Version of Java: 1.7.0_03 Description of Problem: Server threw exception during gameplay (I think after placing an iron pipe or connecting a bunch of iron pipes in a certain way, but not entirely sure), and now throws the exception every time during startup, making the world unplayable. Other worlds load fine. After throwing the exception, the server is not pollable anymore and doesn't accept any connections. Error Messages: java.lang.NullPointerException at net.minecraft.server.ItemStack.doMaterialsMatch(ItemStack.java:243) at ee.TileCondenser.extractItem(TileCondenser.java:539) at buildcraft.transport.pipes.PipeItemsWood.checkExtract(PipeItemsWood.java:111) at buildcraft.transport.pipes.PipeItemsWood.doWork(PipeItemsWood.java:90) at buildcraft.transport.TileGenericPipe.doWork(TileGenericPipe.java:159) at buildcraft.api.PowerProvider.update(PowerProvider.java:52) at buildcraft.transport.TileGenericPipe.l_(TileGenericPipe.java:108) at net.minecraft.server.World.tickEntities(World.java:1182) at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:534) at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:441) at net.minecraft.server.ThreadServerApplication.run(SourceFile:465) Link to pastebin of log: http://sprunge.us/SUAF (entire log for server upstart & shutdown)