If you have saved Mardaneus and the 2 soldiers in Aleroth, you should just have to ask Goemoe about the teleporter scroll after you talk to Zandalor. He will admit he has it, since you saved Mardaneus and proved yourself trustworthy. After that you can ask for the scroll, and when he asks why you want it, mentioning Zandalor should be enough to get it.
