Weird lines appear during motion tween that involve size/shape transforms...

[Demonlove]

Hey guys, I've encountered a strange problem while making my new flash cartoon;
It happens during motion tweens involving a size or shape transformation of a movie clip - For some reason these weird lines appear and flicker on and off while the tween runs. The lines can't be erased, and I have no idea how to get rid of them or what is causing them; it tends to happen when the movie clip is more of a geometric shape like a box or a table drawn using the pen tool. I've attached some images of what they look like;
See the lines? They flicker on and off, its really distracting and annoying.
I've tried to break apart the movie clip and do the size transform as a shape tween rather than motion tween but the lines still pop up RIGHT when I try to change the image's size or shape. It's happened on more than 1 occasion, after restarting the program too so I dont know whats wrong.
As you can see in the images, the lines kind of flicker on and off,change color as the tween runs.
Does anyone know how to remove these/avoid these? I would really appreciate any tips or suggestions. Thanks alot guys!!

[ericlin]

Can you show the swf ? So that I can see the transition.

[martiansam]

I remember facing a similar problem in recent past. All I had done was convert the lines to fill using the option Modify->Shapes->Convert Lines to Fills.

That had solved my problem. Worth a try!

[Demonlove]

That seemed to work, thanks alot! I'll be watching more closely now to see if these lines pop up again, I'll know what to do. thanks guys