i bought AM zign track, but some thing abit strange is happening. after adding my point, i get a prompt saying LOST REQUIRED FEAUTRE , i donot know what to do about this so that i can enjoy Am zign track.

You should contact Luuk Steitner in this forum or go to his web site A:M Track Support and use the support

This can happen when one of the markers moves to fast for the camera to track it, or a marker was not visible on all frames. See paragraph 4.5 in the manual, that explains this in more detail and will guide you through all steps to get a successful track.

You just have to find the frame where the marker gets lost and add enough points manually to cover the fast motion or blured video. After you have done that track it all again. It may take a few attempts to know the safe boundaries of the initial facial acting and how to get the best quality video for tracking.

I just remembered I made a video tutorial on how to track bad videos some time ago because there was another user that was having trouble getting his video tracked. I didn't place it on my website because it's not a very good video, my English may be a bit hard to understand. But it was helpful to this person so it may be to you and others too. (luckily we won't have to go through this tracking setup anymore in version 2)

Here's the tutorial: http://shared.zigncreations.com/trackingtut_01.mp4