I don't have any trouble using hyperlinks or Open URL actions when I export to a Windows Projector. But not a single link works in the Mac Projector exports, from the same Quark file.
I was able to connect to a url on my older Mac (an old G4), but the newer Macs (OSX v 10.5.8) will not pull up any URLs from my presentation. This happens on my client's computer too, which happens to be the same model.
Any solutions? I did try editing the Security settings as described above.