henry,
I don't think you should buy another game; I'm guessing this is an issue related to killaps patch or simply unsolved by the 1.2 official, and has to do with global triggers and such. Thus, buying a new game won't solve it.
I moved on haha - and I'm back to Arroyo already.
Cheers
I am having the same exact problem.
Quite sad, considering it's a major quest in the game and affects the ending.
I'm guessing it's a misplaced/missing trigger issue.