Bryce material files ( .mat ) need to be imported through the material library. Image texture maps ( .bmp, .jpg, ect...) need to be imported in through the picture editor. Which can be brought up by going into the material lab, put a texture into one of the channels, then click the (P) button on the bottom of the texture window, then click the second button on the top left of the texture window. Or the picture editor can be accessed by clicking on the 4 armed guy on the create palette, but that will automatically create and place the image on a 2D face.

Stephen Ray