NICAM channels bundled together after converting DVD video


I recorded one DVD movie and burnt DVD disc for it on DVD-RW. However, I found DVD format too inconvinence for me to backup so I used TSUNAMI MPEG DVD EasyPack Suite and converted the DVD chapter to MPEG-2 format. However, when I played back the converted MPEG-2 file, I found left and right NICAM audio channels mixed into one and all video players available (VLC media player, Windows Media Player, Real player, QuckTimer player) play the audio channels at the same time (that is, I heard 2 languages simultaneously). Could anyone tell me how to fix the problem ?

PS: the audio formats available for TSUNAMI MPEG DVD EasyPack Suite conversion program were MPEG-1 Audio Layer II, Linear PCM & Dolby Digital (default I choosed this).