Looping/sticking problem

Hey all!

I’ve got a problem with the MovieClips within my project. While I’ve pretty much got everything to work how I want, this bug remains.
It occurs when the mouse cursor hovers over a MovieClip (the purple arrow) which is in motion while the timeline on the stage is also playing. I’ve attached the fla in a zip, so hopefully you can try it out and recreate it. I’d attach an avi/swf of it happening but I can’t see where to do that on here.
Any ideas on how I can fix it? It’s quite difficult to describe, but basically the tween seems to get stuck in a 3frame loop or so.

Please help!