Subscribing to a forum isn't really a good idea in my opinion. If you sub to a busy forum all you'll be doing is looking at notifications. Subbing to threads that interest you is the way to go.
For example, if you could sub to the Bayliner section in Boat Manufacturers, do you want to see every time a post is made in the section, whether you have an interest or not?
But I will pass this on to Admin. Thanks for letting us know the button isn't working, SkiDad.