Hi mandledesign
That's the list of users, so its probably related. Are you expecting to send the email to those users who posted in the thread? Or do you want something else to happen?
It seems strange to me that the table is missing. Do you have the original template with the list of people in the thread listed on the right side of the thread view? You would have to find that tpl file but it could have useful info if it is currently outputting the data you need.
Its possible this table is mis-called and there is a real list in the db under a different name.
Given the state of Discuss, you would have to think about how to provide this functionality. However some email notifications do work here on this board...
Let's figure out where the data is, if the db doesn't have the data where Discuss expects it, and go from there.
yes its tough to implement a custom theme with Discuss. Do you have all the bits from the main page template? I can't remember the name of it unfortunately.
Let's make sure you have other stuff, are your site emails working? Do you have the system settings fixed for like site email and so on?
Also what happens when you use the backend to protect a thread? anything or nothing?