an imwarp shifts in fixed vs moving points

hi

using the imwarp function on a 2-d image, i define a corner point (e.g. top left) in the set of 'movingPoints' to be THE SAME as the corner point in the set of 'fixedPoints' - an 'anckor' point. in the resulting image, however, this point is shifted! any ideas on how to remedy this?

thanks a lot !!

mat