Current version of WordPress NextGEN Gallery conflicts with Contact Form 7 Plugin on WordPress 3.4 – the batch uploader throws nasty errors.
According to this bug report, the fix works as follows until there’s a proper update:
$ vim ./wp-content/plugins/nextgen-gallery/ngg-config.php // let's load WordPress #require_once( WP_LOAD_PATH . 'wp-load.php'); require_once( WP_LOAD_PATH . 'wp-admin/admin.php');