oauth callback wrong redirection

[eluser]Unknown[/eluser]
Hi all, I'm working with Elliot Haughin's Twitter library. After twitter login I get this callback redirection http://social.mydomain.com/?/invite/twitter/auth .
Do you know why the "?" is inserted before the uri?

I have set PATH_INFO and allowed query strings. My htaccess is:

Code:

RewriteEngine on
RewriteCond $1 !^(index\.php|robots\.txt|resources)
RewriteRule ^(.*)$ index.php/$1 [L]

Thanks.