Admin link doesn’t work on other blogs when using Network

I’m using the following code in my theme to create the admin link, but it’s not working for my other blogs, only the primary blog.

Any ideas why?

<?php global $current_user; get_currentuserinfo(); if ($current_user->user_level == 10 ) { ?><li><a title="Admin" href="<?php bloginfo('url'); ?>/wp-admin/">Admin</a></li><?php } ?>