ImageReady

I've been using ImageReady alot lately and I have come across something that really bugs me. When I open all my images I have to re-order them in the layer pallette, which is easy and only take a few seconds, but when I open the Animation window they're still all over the place and it takes forever to try and work out where they should be. I try and click the little arrow in the right hand corner of the animation window but where it says 'Make Frames From Layers' I cannot click it, if i'm correct this should fix my problem of the images being in the wrong order in the animation window? Does anyone know why this would be unclickable for me, and know how to fix my problem?
Any help would be much appreciated,
Thanks.