If you are planning to upgrade your WordPress site to their shiny new version 2.8.1 then you will require version 4.0.4 of Simple:Press Forum which fully supports the administration and menu changes that have been made.
Please visit the download page for all the usual download options including a set of patch files for those comfortable with using them.
Between our Version 4.0 and 4.0.4, we have had to make 3 interim updates simply to support WordPress core changes. Hopefully they will leave it alone for a while to enable us to finalise our V4.1 due to be available in beta some time later this month.