[Plugin: Contact Form 7] Warning in Dashboard (WP ver. 3.4)

After plugin upgrade, WP ver. 3.4 display a warning message in Dashboard:

Warning: array_key_exists() [function.array-key-exists]: The first argument should be either a string or an integer in /home/mhd-01/www.jqueryitalia.org/htdocs/wp-content/plugins/contact-form-7/includes/capabilities.php on line 14

To resolve this problem change:

if ( array_key_exists( $cap, $meta_caps ) )
			$caps[] = $meta_caps[$cap];

with:

if (!empty($cap)) {
		if ( array_key_exists( $cap, $meta_caps ) )
			$caps[] = $meta_caps[$cap];
	}

Regards.
Davide.

http://wordpress.org/extend/plugins/contact-form-7/