Qrazi3BoO,
Try storing the video file on the root of the player not in a folder.
Connect the player and right click on it in Explorer and select properties. Is the player use Fat or Fat32 file system?
If Fat32 format to Fat.
Although MTV format is not uncommon in Action chip players the most common video format used is AMV.
Download a sample AMV file from the download section here:
http://www.mympxplayer.org/medium-dc11.html and see if it is recognised by the player.