That code runs for me in PowerPoint, but there is a problem. Because it looks at the web toolbar in the context of the overall application, it doesn't necessarily returns the path to the active file, but instead the last opened or, if later, the file last edited (even if not saved). This inconsistency is troubling; I can't really trust the results.
Something along the following lines hopefully is more useful:
While Excel seems to handle the original function consistently, I think this is safer:
And finally for Word, why not, for the sake of consistency:
bjg1, does that work for your documents (I don't have SharePoint to test)?