When you mouse over a sprite, it will not act as expected. The "zone" of the sprite seems to be some randomly chosen (if at all, in some cases it won't work at all!) area within or near the object that will activate the action.
See capx: DOWNLOAD
Simply move your mouse over the iphone, to make it change animation frames. Notice that it only works when you are near the centre of the object, but not near the edges. In my project, this particular object doesn't even work at all, but in this new example it at least works to some degree.
Hopefully it's an easy fix.