AS3 - Trying to simulate "wrapping" effect

Hello all,

This probably isn’t a hard question for many of you, but I can’t seem to figure out the issue.

I’m trying to simulate a “wrapping” effect for a simulation do the content of 2 identical movie clips creates the illusion of looping content. (The attached file uses very plain, non-identical images for simplicity.)

My move works initially in either direction, but when I try to switch directions, it stops woking. I tried removing listeners to make this stop happening, but to no avail. Perhaps I’m overlooking something very obvious. Regardless, any help is appreciated. Thanks!!

(Note: Mouse over the arrows to move the content.)