Elliot,

I had the same problem a while ago, and it was that my graphics were too far from the Acad 0,0,0 origen. I was working with Coordinates and they were booko far for the Acad origen. Try getting your graphics closer to the 0,0,0.
Acad has this problem revolving fittings or items when real far from the 0,0,0.

Louie