SSP world with a turned on Reactor.
Exception occurs when logging out ("Save and quit" button click).
Code
java.lang.NullPointerException
at ic2.common.AudioSourceClient.updateVolume(AudioSourceClient.java:175)
at ic2.common.AudioManagerClient.onTick(AudioManagerClient.java:97)
at ic2.common.PlatformClient.tickStart(PlatformClient.java:414)
at cpw.mods.fml.common.SingleIntervalHandler.tickStart(SingleIntervalHandler.java:16)
at cpw.mods.fml.common.FMLCommonHandler.tickStart(FMLCommonHandler.java:105)
at cpw.mods.fml.common.FMLCommonHandler.onPreClientTick(FMLCommonHandler.java:361)
at net.minecraft.client.Minecraft.l(Minecraft.java:1432)
at net.minecraft.client.Minecraft.J(Minecraft.java:834)
at net.minecraft.client.Minecraft.run(Minecraft.java:764)
at java.lang.Thread.run(Unknown Source)