IE is very pickie! at ATO->Body, Text & Links->Body Style you don't have a space after the closing ')' in the 'background' rule. You have '...images/bg6c.jpg)repeat scroll 0 0 ;' and that causes IE a problem. Add a space there and you will get the background.
The same issue in the Style Widget
The same thing in the Style POSTS & PAGES
in the CSS Inserts (two cases)
also get rid of the line
margin:0px -10px 10px -30px
in ato->Style Widget->Widget Container
clean all this up and see how it looks