The inability to "Save" Forum settings has been a known issue for a long time. But, that's in a different part of Forum settings. You don't need to select "Save" to unsubscribe from Forum notifications. Just follow the four steps of the instructions in the post I referenced.
That indicates you're no longer subscribed to future forum notifications, but I see you still have more than 99 unread notifications. Apparently it stops counting at 99. Since you're a member of the TV Forum, you would have unsubscribed from notifications for that forum. Hopefully, the emails will stop, or at least be reduced. Please post back if you receive an email for this post. It's unclear if unsubscribing to notifications will stop email notifications for threads in which you've participated. Your post back would be helpful.