It seems that various items cause the avatar to vanish, like thrones wings, the recent animated item, perhaps someone should look into the coding for these
People have found ways to using certain combinations of item to make your avatar disappear, but just one or two items shouldn't cause that.
I just tested Throne's wings and they appear fine in the dressing room for both males and females.
Have you cleared your cache recently? Try un-checking the box marked "show animation" under your avatar in the dressing room?