My widget background picture is only working on the home page.

Site is here: doggonest.com

I've tried adding a background color and image, but then the picture is only on the front page, and the solid color is on the internal pages.

How did you define it?
Where did you define it?

In widget container, under style widgets I have this:

font-size: 13px;
margin: 0 0 20px 0;
padding: 10px;
background-image: url(wp-content/themes/atahualpa353/images/orange60.png);
-moz-border-radius: 15px;
-khtml-border-radius: 15px;
-webkit-border-radius: 15px;
border-radius: 15px;
border: solid 1px #4d4d4d;

try putting a '?' before 'wp-content' or fully qualifying the path to the image
if you fully qualify the path, you could move the image to another folder outside the theme folder and not have to worry about it when you do an upgrade. Something like 'mydomain.com/wp-content/myimages/atalualpa/orange60.png'