Could you please send an example image to support@image-systems.biz? To do so, select the study in the database (imagebox) view and click the export button. Select "open in explorer". No you can copy one of the .dcm files and send it .zip compressed to the above e-mail address.
right click on main viewer and choose autocontrast. If you can see the image, then your getting compressed images. For some reason, I can never see thumbnails from compressed studies, yet autocontrasting lets me see the study in the main vierwer window.