Hi Binh,
I found the problem. Issue is with the new AMV convert tool (MP3 Player Utilities 4.00). I've tried using MP3 Player Utilities 3.68 and converted file played well with my player.

This issue is related to the post:
http://www.mympxplayer.com/viewtopic.php?t=265

Thanks again and more power to your site Binh