im having the same issues, sound wasnt working at first, and now NEI is showing zero items in its display (no it is not turned off so pressing O does nothing) sound came on so as mini said, sound streams and takes a lil bit to download, but whats the deal with NEI, and i can not make either the conversion matrix or the backpack, so dont know what is going on there.
also, when i go to type in the search box for NEI, the game crashes.