To disable e-mail notifications from the Adobe Forums, follow these steps:
Click on Your Stuff
Click on Profile
Click on Manage Email Notifications in the Actions panel on the right
This will list all of the items you are currently subscribed to. You can filter this list to show full forums, indivdual threads, individual users, etc.
There is a checkbox next to each item or a check all option at the top of the list.
Check off the boxes for the items you want to unsubscribe from and click Remove Selected Notifications at the bottom of the list.
That should clear out and stop your notifications.
If this doesn't work, it usually indicates that you have more than one forum account and the subscriptions are part of the other account.
To avoid automatic subscriptions in the future, click Your Stuff and select Preferences, then click on the Email Notification Preferences tab, select No for the items you do not want to be notified of, and click Save at the bottom of the screen.