NoClassDefFoundError in Support & Bug Reports Posted July 23, 2012 Ah, I just downloaded the mod in questions. It seems you may have just stuck the whole zip into the mods folder. Take it out, open up the InfiCraft.zip and read the installation instructions closer to the bottom of the Readme.txt file. Thanks, that worked for my inficraft problem, but now it seems forestry is being picky. Minecraft stays at the Mojang screen if the latest version of forestry is installed for the right buildcraft version. Stack trace? I had to use MultiMC so I can access the error file, is this what you mean: Exception in thread "Minecraft main thread" java.lang.NoSuchFieldError: stump at forestry.plugins.PluginForestryApiculture.preInit(PluginForestryApiculture.java:132) at forestry.core.ForestryCore.load(ForestryCore.java:60) at forestry.core.ForestryClient.load(ForestryClient.java:34) at forestry.mod_Forestry.load(mod_Forestry.java:26) at cpw.mods.fml.common.modloader.ModLoaderModContainer.init(ModLoaderModContainer.java:351) at cpw.mods.fml.common.Loader.modInit(Loader.java:263) at cpw.mods.fml.common.Loader.initializeMods(Loader.java:604) at cpw.mods.fml.client.FMLClientHandler.onLoadComplete(FMLClientHandler.java:203) at net.minecraft.client.Minecraft.a(Minecraft.java:426) at net.minecraft.client.Minecraft.run(Minecraft.java:735) at java.lang.Thread.run(Thread.java:680) On the forestry wiki where you DL that zip, it explains succinctly how to deal with that error.