What are you trying to print? The GL/2 plotter drivers, I believe, are only for vector printing. If the image is composed of color fills and rendered views then you would need to use raster printing driver. That is why it asks if you want to save as a .bmp. You might want to check with your print shop. Most will accept .pdf files and that seems to be the most common file type everyone uses. If they don't have that ability it might be time to find a new one.
Hope this is of help,