A lot of RM files nowadays have spyware "embedded" inside, for example, you might suddenly get re-directed to some websites when you're half way playing the video.

Yes, this is the workaround I used, try to force-open with other players. I believe that it is somehow related to the exploits on the official Real player.

Actually you can just keep your Real Player there (without having to uninstall it), but instead, use WMP to open it (even though it says format incompatible, open it anyway), as I believe it's your Real Player causing the problem, not the codec itself.