please check the forum before posting. this is the news section and your problem is related to some bad video file or software.
@sonmani, what is the error that you get? if possible post a screenshot of the error. alternately, try vlc player. plays almost anything you throw at it.
In case ur using win 7 just download windows 7 media player codec and you will have all your media running on standard and latest version of wmo without any hassle
Here You go: Windows 7 Codecs Pack for Windows Media Player WMP12 and Media Center
VLC and Kmplayer are quite good alternative!