i use this plugin :

http://wordpress.org/extend/plugins/wordpress-seo/

But , when i active that plugin and enable breadcrum function of WordPress SEO by Yoast for my blog . My bbpress breadcrum was been disable . how i fix that .

[onydchicParticipant @onydchic 3 weeks, 3 days ago]

I’m having this problem as well. I want to use the BBPress breadcrumb on Forum pages, and Yoast everywhere else, but I can’t get the bbpress crums to work unless i disable it completely.

[Jared AtchisonModerator @jaredatch 3 weeks, 2 days ago]

I’d try contacting the developer, Yoast, and see if the can add a setting to disable the WP SEO plugins if bbPress is detected (is_bbpress()), which would allow you bbPress to use its own breadcrumbs on bbPress pages and use WPSEO breadcrumbs on all other areas of the site.

Alternative he could also make his plugin disable the bbPress breadcrumbs all together.