Thanks for telling me, I found it here. Another thing, I have a persistent error:
2013-03-24 09:29:11 [iNFO] [sTDERR] java.lang.RuntimeException: Don't register null!
2013-03-24 09:29:11 [iNFO] [sTDERR] at net.minecraft.client.renderer.texture.TextureMap.registerIcon(TextureMap.java:229)
2013-03-24 09:29:11 [iNFO] [sTDERR] at net.minecraft.item.Item.updateIcons(Item.java:726)
2013-03-24 09:29:11 [iNFO] [sTDERR] at net.minecraft.client.renderer.texture.TextureMap.refreshTextures(TextureMap.java:85)
2013-03-24 09:29:11 [iNFO] [sTDERR] at net.minecraft.client.renderer.RenderEngine.refreshTextureMaps(RenderEngine.java:521)
2013-03-24 09:29:11 [iNFO] [sTDERR] at net.minecraft.client.renderer.RenderEngine.refreshTextures(RenderEngine.java:432)
2013-03-24 09:29:11 [iNFO] [sTDERR] at cpw.mods.fml.client.FMLClientHandler.onInitializationComplete(FMLClientHandler.java:247)
2013-03-24 09:29:11 [iNFO] [sTDERR] at net.minecraft.client.Minecraft.startGame(Minecraft.java:475)
2013-03-24 09:29:11 [iNFO] [sTDERR] at net.minecraft.client.MinecraftAppletImpl.startGame(MinecraftAppletImpl.java:44)
2013-03-24 09:29:11 [iNFO] [sTDERR] at net.minecraft.client.Minecraft.run(Minecraft.java:729)
2013-03-24 09:29:11 [iNFO] [sTDERR] at java.lang.Thread.run(Thread.java:722)
2013-03-24 09:29:11 [iNFO] [sTDERR] java.lang.NullPointerException
2013-03-24 09:29:11 [iNFO] [sTDERR] at net.minecraft.client.renderer.texture.TextureMap.refreshTextures(TextureMap.java:102)
2013-03-24 09:29:11 [iNFO] [sTDERR] at net.minecraft.client.renderer.RenderEngine.refreshTextureMaps(RenderEngine.java:521)
2013-03-24 09:29:11 [iNFO] [sTDERR] at net.minecraft.client.renderer.RenderEngine.refreshTextures(RenderEngine.java:432)
2013-03-24 09:29:11 [iNFO] [sTDERR] at cpw.mods.fml.client.FMLClientHandler.onInitializationComplete(FMLClientHandler.java:247)
2013-03-24 09:29:11 [iNFO] [sTDERR] at net.minecraft.client.Minecraft.startGame(Minecraft.java:475)
2013-03-24 09:29:11 [iNFO] [sTDERR] at net.minecraft.client.MinecraftAppletImpl.startGame(MinecraftAppletImpl.java:44)
2013-03-24 09:29:11 [iNFO] [sTDERR] at net.minecraft.client.Minecraft.run(Minecraft.java:729)
2013-03-24 09:29:11 [iNFO] [sTDERR] at java.lang.Thread.run(Thread.java:722)
Edit: I narrowed it down to the spy table part, which is probably not working because it contains a GUI screen. Anyone know what needs to be done to GUIs to fix texture loading in 1.5?