I'm not sure if this fits your problem, but here goes...

I had a problem with scrollbars not appearing on some computers for long forms. It turned out that the scrollable length is influenced by the screen resolution being used. At 800x600, you can view and scroll fine. The same screen at 640x480 will not show the scroll bars. I ended up having to use more pageframe tabs and divide up the info among them. Microsoft confirmed this limitation. They gave me a formula, but I can't find it now.