java.lang.IllegalArgumentException: n must be positive
at java.util.Random.nextInt(Unknown Source)
at enchiridion.api.DisplayRegistry.updateIcons(DisplayRegistry.java:71)
at enchiridion.api.GuiGuide.func_73863_a(GuiGuide.java:210)
at net.minecraft.client.renderer.EntityRenderer.func_78480_b(EntityRenderer.java:1061)
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:944)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:835)
at net.minecraft.client.main.Main.main(SourceFile:103)
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:134)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

Pretty sure this is something I fixed when I did the 1.1 update of Enchiridion for 1.6.4, I should probably update Enchiridion for 1.7.2 too...