Please help a noob with some detective work.
 

Is there any particular way you experienced authors track down what graphic goes where? I've tried to use the Panel Viewer but I just don't understand how it works.

I'm almost done, but I've got a few things I'd like to change, but I don't know what the asset ID is and I can't seem to figure it out just by eyeballing it.

The main things I seem to be stuck on are the borders to the drop-down boxes, and a few of the title bars and borders.

EDIT: I think I've found my problem. I can't open some of the files to change them, such as box_01_titlebar. Photoshop gives me a runtime error and crashes. Is there a trick that I don't know about?