One note: you probably got no reply because you responded to your own post. Moderators look at a list of posts that have no reply to prioritize responses, and since you replied to your own post, you took yourself out of that queue, and made it very difficult for moderators to find and reply to your original post. If you don't see a response from a moderator here, it's probably a good idea to start a new thread for your unresolved issue.
SimplePress is a good forum solution. I'm running the alpha version of 5.0.
It looks like you have that setup and running, but you have some CSS issues with respect to your sidebar. If you can't get those sorted out on your own, you might want to start a separate thread in the theme forum to resolve them.
Hope that helps.