Thanks Lightspeed, I've tried Bestmediaplayer (nice program), but no luck with this file.
Jasondude,
Thanks for the link to the codecs. I downloaded the Mega package, and the updates, installed them all, but still no joy with this file. I am now able to play some other files though, so it wasn't a complete waste of time.
I also downloaded the Gretta file again to make sure I didn't have a corrupt copy. It's a mystery to me why it doesn't play on anything I have. Thanks for the advice though, everyone. It was worth trying.
- Chaz