i not following as much as there is no raycast in that code? Plus looking at that code i cannot see any errors.
Perhaps the error is outside of the code. The way i found the previous error was commenting out most of the code and slowly add things back into play until it stops working.
Is the error from the FPS player or from the other NPC's.
I will have a look in the scene files as well to see if i can find a problem.
Edit: The first time i ran it, both the ninja and jaiqua picked up the chat. Then the second time they stopped working and threw that raycast error.
Also, my mistake and i understand what you are meaning now with the raycast.
Edit2: The error appears when entering the AI Sensors
Edit3: I am now looking in the sensor as i think the error is internal at the moment
copy and paste and make some days very difficult 