I do not crash on this quest and looking at the quest file I don't see any mistakes with it.
That's odd! I've now crashed on it in two totally different games, on two totally different versions (.80 and .87) with two totally different factions (custom faction and Kraxis) and it was repeatable even if I went back and loaded from a saved game. Did you follow the exact same choices I took?
I'll tell you another strange thing that happened with this quest. So yesterday, I was tired of the crashing so I selected a different choice in the first list... I chose "I'll return later" and you know what it did? It still went to the second list of choices! So I chose "pay him" and then I chose "let them play with his gildar" and it didn't crash.