During osCommerce store customization and add-on installation, if you get following error Cannot redeclare do_magic_quotes_gpc():
PHP Fatal error: Cannot redeclare do_magic_quotes_gpc() (previously declared in /home/user/public_html/butikk/includes/functions/compatibility.php:19) in /home/user/public_html/butikk/includes/functions/compatibility.php on line 3
This error is caused by copying of a module file into the languages “catalog/includes/languages/” folder by mistake during some add-on installation. Check all the files in the add-on directories and re-upload them to their destinations. Alsi make sure you don;t mix the catalog/admin/includes/ with the catalog/includes/ folder.
Hope that helps.