[support] Upgrade frmo 6.17 to 7.22 messed up my web site

Hi, I have a web site, hosted at godaddycom that I am maintening for a colleague. We recently receive an advise saying we should upgrade to the latest version of Drupal. I tried yesterday, using the automatic procedure provided by the web hosting company, but it messed up my web site. First error was about unexisting function file_directory_path in sites/all/theme/sky/template.php I did replace any occurence of file_directory_path by file_default_scheme in any file I could find. And now my site display "site under construction". What can I do next? Thanks in advance, Olivier --