Personally, I don't recommend installing packages through the Magento Connect manager. You should always review the code before installing what you need to install on the platform.
One way to do this is by copying and pasting the extension key from Magento Connect on this website: http://freegento.com/ddl-magento-extension.php
By doing that, you will be able to direct download the extension/language pack code and review it. Then you just have to install the extension like any other extension.