Your lights are still overpowering the scene.  You need to examine the intensity of each light and what is its contribution to the scene.  This is a theater set.  Expect the audience section to be shrouded in shadow while the stage is well-lit.  If you are simulating a well-lit room, determine what type of lights are appropriate to evenly illuminate the selected area.  You want to use down-pointing spotlights or area lights to achieve a better effect, and they should be of low intensity.  Too many lights can put a strain on your computer's resources.  Additionally, Poser can only display 6 active light sets at a time in Preview mode, all other lights will not be considered unless one of the original six is turned off.