WordPress Multisite - get_plugin_data()

I use WordPress Multisite. I have multiple sites with plugins installed. I can successfully get a list of the plugin paths with the option value active_plugins from each site.

I can not get additional data from get_plugin data.

I use this code:

$plugins = get_blog_option($blog_id, 'active_plugins');
foreach( $plugins as $plugin )
{
    var_dump( get_plugin_data($plugin) );
}

The error message:

"Warning: fopen(akismet/akismet.php) [function.fopen]: failed to open stream: No such file or directory in C:\wamp\www\blogs\multisite\wp-includes\functions.php on line 3493"

If this is not working on a multisite environment, is there a better way?