Forgotten Homeland Part II bug.

[beastguy]

I'm facing an issue with the quest "Forgotten Homeland, Part II."
After killing the rats and pulling the chain, I walked up the stairs and enter the room. However, the game consistently crashes to the desktop (CTD) whenever I enter that room.
Reloading the save does not resolve the problem.
How to fix this problem?

[beastguy]

After searching the solution on internet, I managed to fixed it by verify integrity of game files.
You can close this case.