I already installed Real Alternative 1.50 in my system. I unable to play a rmvb file with media player classic. An error messege showed that the file cannot be rendered...... This media file, I download by using bitcomet and the file had been downloaded to 100%. This problem always occured, for example: I download single torrent with 10 rmvb file and then download all media files, sometimes at least 1 rmvb file will occur this problem .

I not sure that either is bitcomet problem or real codecs problem...?

Any opinion?

Try renaming to .rm if a .rmvb file fails to play.