You won't like the solution.

The proprietary code created by FrontPage may or may not work in any browser besides IE. It's so bloated it's almost impossible to fix without a major rewrite. I've heard the newest FP version (forget the name, it's not FrontPage) is more standards friendly. I'll believe it when I see it.

If you post the source code or a url someone could look at it and maybe see why it won't display properly but the fix won't be easy. Really the best way to fix it is to take your images and content and start over using a different html client.