I had the same problem and I'm not using an OAuth library. Either way, I just added a # at the end of the redirect URI to clear out any other hash it wants to send you to.

You mean in config file?
facebook.php

$config['facebook_app_id']              = 'xxxxxxx';
$config['facebook_app_secret']          = 'xxxxx

I tried both not working

$config['facebook_login_redirect_url']  = 'oauth/fbprofile#';
$config['facebook_login_redirect_url']  = 'oauth/fbprofile/#';

okay i solve the (redirects to #=) issue is sovled by using redirect();
But i am unable to logout also.....
can anyone say whats wrong with my facebook logout ?

Sorry for my belated response. I wouldn't know what's wrong with it unless you show some code to investigate.