weblinks don't work after exporting to HTML

I have, in the recent past, created a keynote presentation with internal links (to other slides within the presentation) and exported the whole thing to an HTML file. That worked PERFECTLY for me. Now, however, I need to do the same thing (export to HTML) with a different presentation that include external links to web pages. The first external link of the presentation works perfectly, but NONE of the other (very many links!!) work after exporting to HTML. What's going on?

Is it a bug or something corrupted in the file, or can I do something to convince Keynote to work with me on this? This was an older presentation that I had made using keynote from iWork 2008 and I just upgraded it to 6.6.2 format. Can I still use this presentation as an HTML file or am I out of luck? I did export to PDF and the links seem to be working fine there, but I much prefer working with an HTML for the presentation (it looks better than PDF and is it's easier to advance slides and place them properly on the screen).

Any thoughts, anybody?

Thanks!