Microsoft patched
the Restricted Content errors in Windows Vista a few months back, and today
lonely old Windows XP Media Center Edition 2005 is getting its fix. The patch (KB956148) is used to resolve “an
issue in which a Windows Media Center configuration that uses an analog TV
broadcast without a set-top box, displays a protected content message when
recording television shows.”
You should be able to grab the patch from Windows Update, or
if you want it directly go
here.