Texture map problems when rendering in AutoCAD.

I have an exhibit with materials and lights are applied, there are texture maps applied to represent graphics on some of the solids. When I render the front of the exhibit everything looks great. when I render the back of the exhibit where ever there are texture maps applied they render black. I discovered if I rotate the whole exhibit 180 the graphics then render ok but the ones now in the back render black. Anyone know why or has experience this? This only happens with the texture maps everything else renders ok.