It is by design that you loose the teleporter stones on entering act 4. <img src="/ubbthreads/images/graemlins/disagree.gif" alt="" /> When the imp gave them to you he said he would be back to get them, but there is no cutscene or anything to explain that that is why they are missing.
Which dungeon are you having a problem with? The BF dungeons are randomly generated, but for the main game there are
Maps as well as a
Strategy Guide to consult, or you can describe the dungeon and the stones you are trying to use.
