Possible bug: DONOTCACHEPAGE already defined

Hello,

I have multisite installation and when I disable caching on the Network Admin Sites page I get the following notice:

Notice: Constant DONOTCACHEPAGE already defined in /wp-content/plugins/wp-super-cache/plugins/multisite.php on line 50

It seems the problem is in the following function:

function wp_super_cache_override_on_flag() {
	global $cache_enabled, $super_cache_enabled;
	if ( $cache_enabled != true )
		return false;

	if ( get_option( 'wp_super_cache_disabled' ) ) {
		$cache_enabled = false;
		$super_cache_enabled = false;
                define( 'DONOTCACHEPAGE', 1 );
		define( "SUBMITDISABLED", 'disabled style="color: #aaa" ' );
		if ( is_admin() )
			add_action( 'admin_notices', 'wp_super_cache_multisite_notice' );
	}
}

This fixes the problem:

    if (!defined ('DONOTCACHEPAGE')) {
      define( 'DONOTCACHEPAGE', 1 );
     }

Please check.