In our last episode, I wrote some rather dire things about being careful about moving HUDs around because they and their inventory can be lost. If you have been affected, you might be interested in this JIRA entry (log in and vote if you want to get Linden attention on the matter!) and also a recent blog entry (and another) from Keiki Lemieux about getting Linden support assistance.
Some anecdotes suggest that it might be less risky to do things one at a time. That is, don't try to wear a HUD that is rezzed on the ground, or replace one attachment with another. Instead, detach or pull objects into your inventory first, then wear in a separate step. That does seem like a reasonable possibility, since you are hitting the servers with fewer transactions at once that way.
If you have especially valuable no-copy animations and are afraid to lose them, it might even be safer to use them the hard way for now: play them directly from your inventory so there is no rezzing involved.
