Hope this doesn't belong in the newbie forum!

I'll try to explain my issue as well as I can, since I'm unable to upload the fla from here.

I'm making a photo slideshow with clickable thumbnails. The thumbnails move in response to the position of the mouse, so I have all the thumbnails inside one horizontal bar-shaped movieclip (box2_mc). Each thumbnail inside that MC is an instance of one movieclip, named t1_mc, t2_mc, t3_mc, etc. There are 16 thumbnails, but only 8 coded so far. I'm using the following to interact with them:

box2_mc.t1_mc.addEventListener(MouseEvent.CLICK, t1addPic);
box2_mc.t2_mc.addEventListener(MouseEvent.CLICK, t2addPic);
and so on.

The odd thing is that the first 4 thumbnails will not respond when clicked at first. However, once I've clicked on one of 5-8 (which will respond), 1-4 become responsive.

I've scoured the MC for invisible bogey-men blocking it, but to no avail.

Is there an obvious solution here? Or, at least, is there something I could use to trace() back whatever I'm clicking on? More information needed? (curses to my lost thumbdrive or I'd upload the fla)