If you run into issues with synchronizing your TV program guide in Windows Media Center 2005, and the issue is either a Code 13 or 33 error do the following:
1. Open up the Date/Time control panel.
2. Make sure your date and time are properly set. (if they weren't, try downloading the program guide again).
3. Click on the 3rd tab, which controls network time synchronization.
4. Try sync'ing to time.windows.com or the NIST server.
5a. If this fails, make sure that Port 37 is open on your firewall.
6. Once Port 37 (Network Time Protocol) is open, you should be all set and your program guide should download fine.