I was having a little problem with IW's veiwer. It seems that hair was in a place where a HUD would go.
I was told to do the following:
1. Set bandwith to 1200
2. Set cache size as high as you can. I set mine to 980
3. Clear cache
I was also told to use Imprudence veiwer, but was also told the InWorldz veiwer is better than Imprudence. I guess that's your preference.
There was the same problem on another grid and was told to just hide HUDs.
Whatever works for you.