As the author states on the description page he "creates a post_expire column on the posts table". This is one of the worst programming technics in a WP plugin I've seen up today. It is similiar to changing the core files of WP.
So I'am not wondering that a virus scanner may flag this. There are other ways to deal with an expire date which conform with WP guidelines.
Despite all these interesting features I recommend not even to install this plugin.