I had the same problem, using Viewer 2. I went into the inventory and tried removing everything that I thought had a script e.g.. Ass, to reduce the number of bytes that the avatar was drawing, thinking that this was the problem. That didn't work. Then I downloaded and installed the Phoenix viewer. That worked, and I can now see my avatar OK. However, the downside is that with Phoenix a lot of times the rest of the environment doesn't rezz very quickly or at all, whereas I had the reverse situation with Viewer 2, where I could see everything except my avatar.