We've tested the application on a variety of platforms, including Windows, Mac, and Linux, with myriad versions of browsers. In my experience, IE5 on the Mac has a lot of rendering problems not just with MileTrak but with a lot of other Internet sites as well. I think the issue is that IE5 on the Mac is not smart enough to recognize that an anchor (#whatever) doesn't mean, "jump back to the sign-in page", but rather, "jump down the current page".