Make sure that you are not entering any characters other than letters and number is any of the form entry boxes. For example, the phone number should be 1231231234 and not (123)123-1234. The credit card number should not contain dashes and your street should not be "Main St." (with a period), but "Main St" or "Main Street" (with no period).
That's the most common reason for what you are encountering. I realize that it is truly a stupid requirement and totally useless messaging, by the way. :-(
If you need to contact customer service -
How to reach support (FAQ) - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=2421771&SiteID=2
-steve