Well here's is something I never expected: the mod is conflicting with itself!
java.lang.IllegalArgumentException: Slot 237 is already occupied by ic2.advancedmachines.BlockAdvancedMachine@5b5ede11 when adding ic2.advancedmachines.BlockAdvancedMachine@31455cf4
at yy.<init>(Block.java:212)
at ba.<init>(BlockContainer.java:16)
at ic2.advancedmachines.BlockAdvancedMachine.<init>(BlockAdvancedMachine.java:38)
at mod_IC2AdvancedMachines.load(mod_IC2AdvancedMachines.java:120)
at ModLoader.init(ModLoader.java:830)
at ModLoader.AddAllRenderers(ModLoader.java:186)
at wb.<init>(wb.java:76)
at wb.<clinit>(wb.java:9)
at net.minecraft.client.Minecraft.a(SourceFile:265)
at net.minecraft.client.Minecraft.run(SourceFile:644)
at java.lang.Thread.run(Unknown Source)
--- END ERROR REPORT d7effb97 ----------
Help?