Movieclip Tween Problem

programming flash
1

Hey All,
i m using robert penner’s tween example for sliding my set of images.
there are 4 images in a row…all is going fine except that when we rollover 4 th image and roll back on 3rd image the tween is not right…rest all are working fine…
can anyone fix it…plzz

here is the example

Thanks in advance!!