Are you using the 2.0 Beta or 1.6?
Support for 2.0 Beta - http://help.live.com/help.aspx?project=onecarev2 - use the "Get More Help" link in the lower right of the page to contact support via email.
Support for v1.6 is via the information here - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=1183038&SiteID=2
See the Bug Submission Guide - http://connect.microsoft.com/content/content.aspx?ContentID=3480&SiteID=168 - for details on how to create and submit the Support Log zip file with your bug.
-steve