External Hard drive automount problem
You probably have a folder named /Volumes/Drobo, so it has to pick a different name to mount the drive under.  In one sense, this is fairly easy to fix: just rename/move/delete that folder, remount the drive, and you're set.

But it's probably more complicated than that because you probably have something set to automatically access something in /Volumes/Drobo, and when that doesn't exist it'll recreate it (which is probably what caused the problem in the first place -- after the port failure, the Drobo didn't remount in time, and whatever it was created an empty folder where it should've been).  So, you'll need to figure out what's recreating that folder, and get it to stop long enough to do the rename and remount operation.