The 'Drobo' there is connected to the office computer.
I access it via Finder, or via a 'Favorite' in Bridge.
Just checking now, any program that uses Finder to find files and folders, (such as Dreamweaver) can access the Drobo or any folder on the office computer.
... and in checking again now, I see that PHoto Mechanic does in fact see the Drobo now. So who knows what went wrong earlier today.
Case closed. Thanks for the help!