error code C00D1169

I have a DVD which I have played few times on this same Vista computer. But today when I tried playing it again in Windows Media Player, I got an error message saying:

Error Code C00D1169
Windows Media Player cannot play the DVD because the disc prohibits playback in your region of the world. You must obtain a disc that is intended for your geographic region.

It sounds very strange because I was able to play this earlier. Anyway, can you guys please explain me this error and please provide some solution to get rid of the same. Thank you.

Before I can provide you some solution, would like to know few things. Are you using any DVD filter with your system, if yes, which one? Is your monitor connected to your PC via VGA, component, or HDMI cables? Also did you checked WMP's Help:about:Technical Support Information menu tool under the "MPEG filters" section? What is it showing up?

If the video / vob / mpg you are playing as on an ext hard drive, share the drive and give everyone access, that will stop WMP from saying wrong region.

If the video / vob / mpg is on an internal hard drive, do the same. It has something to do with the security on vista and XP

Havent tried this but try running WMP as Admin by right clicking over it and clicking "Run as Admin.." then open the video / vob / mpg from within wmp by using the File Open Menu's