It looks like you're missing a background image. You might want to check base_box_center_silver.
Honestly, it sounds like you need to be more careful with your code. Wicked is right. Check every line in the xml. Is the image name correct? Does the file exist? Is it in the right directory? Start small. Get the code working before you add more.
It sounds like you're on the right track with your testing. That's probably faster than waiting for a forum reply. Unfortunately you need patience either way.
As the saying goes, patience is a virtue... (it gives you non-combat power regen).
My trick for finding an image file in the game ui is to replace it with a bright pink tga. It's usually easy to spot. I'll admit that it took me months to find the purpose of the background image on the housing permissions window though.