I recently downloaded some music videos in .avi format and played them successfully on a PC in Windows Media Player (XP, version 9).
I then burnt these files onto a CD and subsequently copied them onto another PC, also running XP and WMP verison 9. However, on play back on this other PC, the WMP player searches for a codec ('sending codec request...')but returns the message 'codec error'. The files then play as audio files only. This happens whether I am online at the time or not.
I'm afraid I don't know the answer but may I suggest that you post your supplementary question as a new thread. The reason i suggest this, is that your initial thread was ticked as resolved, and therefore people who may know the answer may not look at a resolved thread!! (I only looked as I am relatively new to all this and I try to look at as many threads as possible, easpecially concerning media items).