That's a pleasant style, but I'm not familiar with AEF, so I don't know if this style is common, or if you've modified it at all (assuming you didn't create it entirely, of course.)
In any case, as you've just started your forum, have you thought about lessening the amount of forums and sections you have, so that you can concentrate on building up content for fewer sections, and so as to help off-set the feeling that there's no activity? As your participation and amount of participants increase, then you can add the forums and sections back. For now, you can either hide them, or make a few sub-forums, if you so choose to go with this suggestion.
Finally, I see you have a welcome message within your first forum, but I wonder if your software supports a welcome message for display near the header, just below the navigation bar? This would be a better place for a welcome message, I believe, as it would be far more visible, which is important since most guests are going to be spending mere seconds before deciding whether to leave or keep browsing.
Looks good, only thing i would do is switch the width over from full screen to designated. If it does not allow you to do this in the Dashboard then you will have to find the dimensions in the index.php or other files. Have not used this program so i'm not sure but it should be in the theme directory you choose.