I no longer have the e-mail account I used when setting up Active Forums. How do I stop it from sending notifcations to my old account? I've looked under my user settings but can't find it. Is there perhaps a setting where it sends all posts to a master account that I need to change?

If I am not mistaken you should be able to adjust this in the forums section in the control panel. Check for each forum/forum group.

Good luck.

Sounds like you have a user account with the email address still subscribed. Go the DotNetNuke users page and search by email address.