My aim functions is not working as planned
 

When I choose my rocket ship (following Mastering Maya Complete 2) and then Shift+select a spot light, then add constrain--->aim, I am not getting the desired result. Instead of aiming at the ship always, it aims at some cock-eyed far off point and moves undesirably when I move the rocket. Please help, it seems to be a glitch in my system and I was wondering if anyone else have had the poroblem and if they can fix it.