After updating IC2 from 1.43 to 1.64, my existing SMP server is reporting this:
2012-01-25 22:34:26 [INFO] ModLoader Server 1.1 Initializing...
2012-01-25 22:34:26 [INFO] Mod Loaded: mod_BuildCraftCore 2.2.12
2012-01-25 22:34:26 [INFO] Mod Loaded: mod_BuildCraftBuilders 2.2.12
2012-01-25 22:34:26 [INFO] Mod Loaded: mod_BuildCraftEnergy 2.2.12
2012-01-25 22:34:26 [INFO] Mod Loaded: mod_BuildCraftFactory 2.2.12
2012-01-25 22:34:26 [INFO] Mod Loaded: mod_BuildCraftTransport 2.2.12
2012-01-25 22:34:26 [INFO] Mod Loaded: mod_IC2 v1.64
2012-01-25 22:34:26 [INFO] Mod Loaded: mod_RailcraftAutomation 3.1.0
2012-01-25 22:34:26 [INFO] Mod Loaded: mod_RailcraftBuildcraft 3.1.0
2012-01-25 22:34:26 [INFO] Mod Loaded: mod_RailcraftCore 3.1.0
2012-01-25 22:34:26 [INFO] Mod Loaded: mod_RailcraftExtras 3.1.0
2012-01-25 22:34:26 [INFO] Mod Loaded: mod_RailcraftFactory 3.1.0
2012-01-25 22:34:26 [INFO] Mod Loaded: mod_RailcraftInfrastructure 3.1.0
2012-01-25 22:34:26 [INFO] Mod Loaded: mod_RailcraftRails 3.1.0
2012-01-25 22:34:26 [INFO] ModLoaderMP 1.1 Initialized
2012-01-25 22:34:26 [INFO] Starting minecraft server version 1.1
2012-01-25 22:34:26 [INFO] Loading properties
2012-01-25 22:34:26 [INFO] Starting Minecraft server on *:25565
2012-01-25 22:34:26 [INFO] Preparing level "htworld"
2012-01-25 22:34:26 [INFO] Default game type: 0
2012-01-25 22:34:26 [INFO] Preparing start region for level 0
2012-01-25 22:34:27 [INFO] Preparing spawn area: 89%
2012-01-25 22:34:27 [INFO] Done (1168622269ns)! For help, type "help" or "?"
2012-01-25 22:34:28 [SEVERE] Unexpected exception
java.lang.NullPointerException
at jm.a(SourceFile:274)
at ic2.api.Ic2Recipes.getOutputFor(Ic2Recipes.java:151)
at ic2.api.Ic2Recipes.getCompressorOutputFor(Ic2Recipes.java:83)
at ic2.common.TileEntityCompressor.getResultFor(TileEntityCompressor.java:61)
at ic2.common.TileEntityCompressor.operate(TileEntityCompressor.java:84)
at ic2.common.TileEntityElectricMachine.l_(TileEntityElectricMachine.java:105)
at fq.f(World.java:1204)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:441)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:346)
at cz.run(SourceFile:465)
Starting a fresh world works fine, but I'm more than a bit reluctant to tell my users that their world has ended...
Thanks in advance for any help on this.