I'm going through Gothic II now, and I think I may have run up against a problem that could prevent me from completing the game. Vatras has given me a letter to Saturas, but I don't get a dialogue option to give Saturas the letter. I've already taken Lares' ornament to him, but there doesn't seem to be anything else I can do.
Following the main plot, I seem to be irreperably stuck:
I need to get the Eye of Innos, but can't do so because Vatras won't help me without a water mage to come and relieve him.
For a water mage to come and relieve Vatras, Saturas first has to get open that Portal that everyone's going on about.
To get the Portal open, I need to do something... but Saturas won't take my letter and tell me what.
Is there a way I can work around this, or do I have to start over? Because I've been playing this game for well over 20 hours already and the prospect of beginning again is, at best, very disheartening.

Nevermind; I was able to talk to Nefarius (what a name...) and complete the Portal quest anyway. The plot is proceeding as normal now.