Dříve ti to přehrávat šlo?

Stačí číslo tý chyby dát do Googlu... a najdeš např. http://forum.zive.cz/viewtopic.php?t=24263

Přímo na stránkách Micro$oftu:

C00D1197: Cannot play the file
Windows Media Player cannot play the file. You might encounter this error message for one of the following reasons:

* Your computer is not connected to the local area network (LAN) or to the Internet. Connect to the network or Internet, and then try again.
* The path to the file is not valid. If you typed a Uniform Resource Locator (URL) in the Open URL dialog box, ensure that the file name is spelled correctly and the path to the file is correct, and then try again. If you clicked a link on a Web page, the link might not be valid.
* The server is not online or is busy. Try again later.
* Some network protocols in the Player are not enabled. Enable all network protocols, and then try again.
* The proxy server settings for the Player are not configured properly. Verify that your proxy settings are correct, and
then try again.