Hi, I was flying away from by base when I crashed.
I think its the Ic2 sound unloading after I left the sound radius from my geothermal generators.

Time: 9/25/15 7:07 PM
Description: Unexpected error

java.lang.NullPointerException: Unexpected error
at paulscode.sound.SoundSystem.removeSource(SoundSystem.java:1258)
at ic2.core.audio.AudioSourceClient.remove(AudioSourceClient.java:73)
at ic2.core.audio.AudioManagerClient.removeSources(AudioManagerClient.java:261)
at ic2.core.block.generator.tileentity.TileEntityBaseGenerator.onUnloaded(TileEntityBaseGenerator.java:97)
at ic2.core.block.TileEntityBlock.onChunkUnload(TileEntityBlock.java:72)
at net.minecraft.world.World.func_72939_s(World.java:1979)
at net.minecraft.client.Minecraft.func_71407_l(Minecraft.java:2006)
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:973)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:898)
at net.minecraft.client.main.Main.main(SourceFile:148)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

@Bluedog444 again here... Please tell me if that happens with 1.2.0.0

@Speiger Oh these were very old versions of the mod. I doubt it happens now.