See this post for the KB article to troubleshoot install problems - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=1588602&SiteID=2
How to reach support (FAQ) - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=2421771&SiteID=2
Since you have not yet activated the subscription, support will be via email.
Unofficial path - send me an email at sboots@mvps.org with a subject line including "OneCare" (to get past my spam filtering) and in the message body, tell me what country you are in, your forum nickname, and paste this link:
http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=4082378&SiteID=2
I am not online 24x7, so you may be waiting for a reply, but I'll do my best to hook you up with support.
-steve