So now I'm playing Gothic 2, and I've run into a glitch. I'm trying to complete the "Weed Dealer" quest for the militia, and in order to progress I need to ask Nadja in private about where to purchase some.
I accidentally paid for a "night of fun" with her but didn't immediately follow her upstairs. After 24hrs in game time, she went back down stairs into the lobby. I tried to get her to go upstairs again but the only talk option is "Where can I buy some weed?"
I tried to purchase another night from Boromor and the only option is "END". I completed the Boromor's bowl quest for the free night of fun, but all he said was "Thanks" and I gained 200 xp. Is there something I'm not trying here? O.o

I`ve never had this situation before. Does she answer the weed-question? Maybe it works again, after you`ve done the Milita-Quest

Gothic 2 is full of little glitches that they never got around to smoothing out. If all else fails you might try using the cheat console/'Marvin' mode to reset an npc or quest.

http://www.worldofgothic.com/gothic2/?go=g2cheats

After extensive searching, the only solution to this is to unfortunately abandon this quest or to restart the whole game. :(
Sad day.