Guest posting no longer allowed on forums with ads
ForumUp forums have now been set so that posting by guests (unregistered users) is not allowed anymore with forums that have the ForumUp advertisements. This was done to help prevent the problem of spam postings. Some computer program spambots have the ability to make posts on forums that allow guest posting, and most of those spambot posts are inappropriate content.
The way to have the feature back to allow guests (non-registered members) to post is to pay to remove the advertisements on your forum. However, it really is not a good idea to allow non-registered members to post, since that also allow spambots to post.