I read this post looking for a solution, and I thought I would post my success after trying a combination of solutions. I was having a very hard time getting the avatar to load. I went from viewer 3 to viewer 2, and had no luck. Anyway...I think this is the absolute last resort.
1) Log in using viewer 1
2) detach all objects, take off all clothing.
3) Edit appearance, and take off items missed in the "detach all" and "all clothes"
4) try to wear a default avi, and change the hair base
That fixed it for me. From there it was just relogging in viewer 3 and getting set up again.