I'm sorry that you've encountered this problem *and* have now waited a few days for a reply here in the forum. See this post for how to contact support:
How to reach support (FAQ) - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=2421771&SiteID=2
On your specific problem, what is the media type that you are using for backup? CDR, DVDR, CDRW, DVDRW? If you are using RW media, try using R media - write once. Do you have other burning software installed on the PC?
-steve