Try to install bbpress via your administration yoursite.com/wp-admin/plugin-install.php
If you are unable to install plugins via administration (it is asking you for your FTP credentials), you can enforce using of direct FS method by adding following to you
wp-config.php
define('FS_METHOD','direct');
Else, the correct path for adding a new plugin is in
./wp-content/plugins/
. If you downloaded a .zip file, make sure you upload the unzipped files (the whole directory) to the location above (with the wrapping folder of course).
If you have got the files in correct location and WordPress still can not see them, make sure those files have a correct permissions and group ( see http://codex.wordpress.org/Changing_File_Permissions )
And one last trick, try to enter your permalinks settings screen in administration right after you upload your plugin, that’s something like “restart” for WordPress.
