[Ashish Kumar (Ashfame)]

WP 2.7.1 and bbPress 0.9.0.4 can’t be integrated natively because of the way they handle cookies. Either you downgrade the method used by WP or upgrade the method used by bbPress. Both the method can be done via plugins (You only need to use one of them).

For WP plugin:

http://superann.com/2009/02/26/wordpress-26-27-bbpress-09-cookie-integration-plugin/

For bbPress plugin:

https://bbpress.org/plugins/topic/freshly-baked-cookies/

I have used the bbPress plugin to get them in sync.

Hope that helps.