BuddyPress.org

I receive this error, “The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator and inform them of the time the error occurred, and the actions you performed just before this error.

More information about this error may be available in the server error log.
Apache Server at http://www.techgreet.com Port 80”

Whenever i try to access the replies tab in my site, other tab like Forums, topics and new reply working fine but only replies tab is not accessible at all.
I have tried increasing php memory, disabling and enabling plugin,creating new .htaccess file but still unable to solve it out.

Please help me as i am totally confused with angry with BBpress.