Vanilla NEI Fix is a tiny core mod for Minecraft 1.4.7 that fixes a compatibility issue with NEI and the modern vanilla launcher (which CurseVoice also uses).
NEI expects to find a minecraft.jar somewhere in the classpath, but for the modern launcher your Minecraft jar can be named anything. This mod detects what jar is being used, then patches the appropriate method in NEI.
Note: This is a core mod! It goes in your "coremods" folder.