Did you choose no email notification under Default Thread Subscription Mode? If so, it may be because you're already subscribed to receive emails from those threads.
http://www.yorkietalk.com/forums/subscription.php Click there and to the right it will say what type of notification you're receiving.
I do not have this problem so I'm not entirely sure if you can stop emails unless you unsubscribe. You can immediately go back in and re-subscribe under "Thread Tools" under each thread.
