Did you recently make a new ID and try to add all your old buddies back to it? When I did that and tried to re-add everyone, I had the same problem, couldn’t add, delete or move anyone from group to group after about 10 or 15 people. I guess it’s a yahoo thing, daily limit or something. It takes a day or so and then it goes back to normal, but it seems like for the next few days after this happens it’s kinda picky and you can only add a few people a day….