Someone ran into the same problem awhile ago in the old forum, but after transferring the saved game to another computer and loading it there the teleporter stone showed up again. If you had it on the ground when you installed the patch, whatever caused the black map may have took out the teleporter stone as well.
If you don't want to wait for a fix for the map problem, you can put the teleporter stone you still have in a chest somewhere and download a replacement set.
Lost Items - guide and directory of inventory files 
