Hi, welcome to the forum <img src="/ubbthreads/images/graemlins/wave.gif" alt="" />, Boridog.
The teleporters are supposed to work after you get them back from the imp.
They don't work
in the Imp's world (Imp Council quest)
if you've got both in your inventory
if one is in a container, barrel, chest etc.
maybe if you encounter the black map problem or have a corrupted save. Black maps: When your area is dark again although you had explored it thoroughly.
Where are yours?
Kiya