Help on the background of '20th century Fox intro'

I am new to blender. After downloading the ‘20th century Fox intro’ blender file, I tried to render the file. But no sky appears. I do choose world->texture and selected my sunset.jpg and the preview in world button is pretty good. But when rendering, the sky is always gray, no sunset pictures was displayed. Anybody can provide me some clue? Thanks

Where did you get this file? Which version of Blender was used to create it? And which version of Blender are you using to look at it?

I have the answer, under the texture->Influence check the Horizon check-box and adjust the lever as desired, your clouds should now be visible. (this is for blender 2.59 so if this is not your version, then it may not work that way).