Your last questions there... No, to both of them. First off, you can put as many lights as you can in a map. x3 And they take effect all the time, although they may not be as obvious unless you got your character close enough to realize the difference in lighting. Nyan colors might do best, too, on the subject of lighting and stuff.
What you said firstly, though, I've never heard of. I'm not sure what's wrong there - Perhaps you can provide more details, like if they're always the same kind of lights and stuff?