See what happens if one of your co-workers logs onto your machine with their logon.
If it works for them, then it could be something in your profile. However, I would expect that to affect all projects. Anything is worth a try though.
See www.grainge.org for RoboHelp and Authoring tips
How's this for whack, yo....As you suggested, I had a coworker log onto my machine. She opened the troubling project just fine. Here's where it gets weird. She logged off, I logged back on, opened the project and voila', everything works just fine. Really weird. Before that I would get hung up as described in my original post. I don't think I'll try to understand this - just accept it as some sort of divine Adobe/Microsoft intervention. Thanks for the suggestion!