Re: Fatal error entering general settings from admin
Your server is running out of memory. That doesn’t normally happen on a default installation. What plugins or modifications have you added, if any?
You can request more RAM from the server (or host) but it would be good to see why this is happening.
Also, did you integrate with WordPress? That’s an error from WordPress. Additionally, did you install bbPress as a WordPress plugin? It’s not a plugin for WordPress.
Need more information about your setup please.