How to get an MPG2 to play in SD that plays in WMP?

I'm assuming this isn't a bug, just something I haven't learned yet. I have saved a few children's programs from TV, converted them into .MPG files and saved them to my G4. They will play fine in Windows Media Player (as long as SD is completely closed, otherwise no video), but they will not play in SD. I get that error screen detailing the file and saying that it can't play that file (likewise, audio rolls in the back for the file). What am I missing? Obviously I have the CODEC on the computer since it can play, but it doesn't seem to play nice with SD. I have the latest (1.1.1.0) and each video file is about 900mb. I'm running in -testmode to enable video. Any thoughts or ideas?

I think you should download another codec pack and intall
http://www.xpcodecpack.com/

I use this and work perfectly... Hope this help

Thanks, I'll give it a try. My car is in the body shop following an accident 3 weeks ago, but when I get it back I'll see if this solves the problem.
*update* Seems to have helped out for most files, but still run into some videos that report the proper codec isn't installed.