I'm getting a lot of "Class not registered" errors with quite a few files these days, and I'm just wondering if their's anything I can do about it?

All of the files this happens to are standard formats: avi, mpeg, wmv etc, but a number of these will not play. The Real Networks help site isn't very much help. Something's either wrong with my player (which there is not), or somethings wrong with the file, which seems to be the case. But what? Why are people uploading so many corrupt files?

Or, is there a codec or something I could get?

Thanks

Loran