Nero Showtime. Audio/Video Not Sync. ??!!

[Timmy.]

Howdy, I have Nero Ultra Edition with Showtime 3 n all. When I first used Showtime I liked the quality so i started using it. After using it for awhile the audio/video timing was off. I watch anime series with it. So most of them are MKV files. In DivX they play perfect. So just wondering if any of ya'll had a clue and even a solution. If any questions jsut ask Ill answer.

Thanks, Tim