If you really are paying for this forum then ORDER THEM TO STOP USING THOSE POP-UNDER ADS!
They appear as a new window, drop to the background, load way too much data(which takes about 30secs on my 56k), and then pop-up with the close-box hidden and a linked-graphic that looks-like the close box displayed! Right-Click is also disabled, making it almost impossible to close the window without crashing the Browser!!!