He can 'quit' all he wants, doesn't mean jackshit unless the board accept it which they didn't because it's obvious he was going to Aston Villa so they want compensation which they're well in their rights to do.
Yeah but it matters little if the board accept it is what I'm saying. If you have a valuable member of your work team saying they're quitting yet you're the boss and you don't like it, you can't force them to stay in the job. Lambert quit, regardless of if it's accepted or not. Done.
As for the compensation, Norwich may not even be given any as they broke a clause in Lambert's contract by refusing him permission to speak with Aston Villa. The clause states he's allowed to speak with other Premier League clubs, so the only way I see Villa giving them compensation is to smooth things over a little, possibly paving the way for them to go after a player like Grant Holt and not have the two clubs at each other's throats, if you get what I mean.
If Villa took their manager and paid no compensation, then want to buy Holt, they'd get the middle finger, and probably rightfully so. If they don't have to pay compensation and do anyway, Norwich may be inclined to listen to offers. Either way, Lambert quit, he's going to Villa, and there's nothing Norwich can do about it.