wallpaper help?

Hi, I have vista and am currently running Litestep version 0.24.8. When I load my computer my background is always black, even if I set a wallpaper before I shut my computer off it just takes it off after I restart. I've tried a few different codes in my theme and step.rc, but nothing I do seems to work. I'm really bad at coding though so I was hoping someone would be able to help! If you can help me I would really appreciate it!