exporting alignment to Google Earth (not coming exactly)

I have 50 kms of alignment , I am trying to export it on google earth from MX. I am following usual method by defining placemark and then exporting it to google earth. I have taken start point as place mark, when I am transferring it to google earth, start point is coinciding with google earth placemark, but rest of the alignment is not coming exactly on google earth as it should come exactly on same coordinates.

Pls help.