problem uploading new theme

I just added wordpress (version 2.6.2) to my godaddy hosted website – and am anxious to put all of my content up on it, but I can’t even change the theme! The directions say “you generally just need to upload the theme folder into your wp-content/themes directory” but every time I plug in http://www.nojunkfood.org/wp-content/themes.php it goes to an error page. Could you please tell me where I go to upload a new theme/layout? I downloaded the new theme, i just don’t know how to get it onto my site. Thanks!