Go to http://account.live.com and verify that your country is correct in your profile.
Open IE and make sure your language is correct for your location.
Delete cookies and clear Temporary Internet Files.
Close IE.
Try activating OneCare again.
If the form is still incorrect for your location, please contact support via email as a trial user:
How to reach support (FAQ) - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=2421771&SiteID=2
-steve