My immediate guess is that you're putting textures on LAMBERT 1. DONT DO THAT Lambert 1 is the default shader for all geometry created in Maya.

Obviously you're working with polygons. Are you texture mapping these using the various texture mapping methods? i.e. Planar, Cylindrical, Sphereical, Automatic? Using one of these should clear the image in the background. Otherwise, there's a button in the UTE to turn off the background image. It's the one with the picure of the kid on it.