Somebody I know has a website made in FrontPage XP using a template. The template was slightly customized by another designer and been used regularily for about 4 years. Now for some reason, the areas in the table where the navigation goes seems to be corrupt. It says "click to add..." but it won't actually let you. Copying and pasting into it won't work. Creating a new page won't work either - same problem exists.
Not sure what's happened and since I don't use FrontPage very much myself, it's totally baffled me. Perhaps the person who does the website updates messed something up? Does this sound familiar? If there's an existing thread on this topic, or any thoughts, please let me know.
I recently had a very similar thing happen - I wasn't using FrontPage but I was using a template (that I had made myself). It did turn out to be a file corruption, but it was in some of the content I'd added, not in the template.
If there was anything added to the site, especially any images or any material imported from another site, just before the problem started, you might try deleting that content and see what happens.
If this is the problem, it can be misleading. Because it's a function of the template that's affected, it's natural to think the problem is in the template itself, but in my case, at least, that turned out not to be true.