The @drupal installer failed to create a %file file with proper file ownership. Log on to your web server, remove the existing %file file, and create a new one by copying the %default_file file to %file. More details about installing Drupal are available in <a href=":install_txt">INSTALL.txt</a>. The <a href=":handbook_url">webhosting issues</a> documentation section offers help on this and other topics.