just loaded up the dw 1.6.4 pack and noticed the just about every mod in the pack is missing this file. any attempts to load a save result in a ctd with no error message. What follows is what appears in the console regarding the missing file:
pack.mcmetafile missing?
2014-01-10 14:40:45 [WARNING] [Forge Mod Loader] Mod Forge Mod Loader is missing a pack.mcmeta file, things may not work well
2014-01-10 14:40:45 [WARNING] [Minecraft Forge] Mod Minecraft Forge is missing a pack.mcmeta file, things may not...
pack.mcmetafile missing?