See here [[Export Firefox bookmarks to an HTML file to back up or transfer bookmarks]] I see that you have firefox 23.0 on your desktop...I advise you to update your version here [http://www.mozilla.org/it/firefox/new/ Mozilla.org]

Firefox stores the bookmarks and the browser history in places.sqlite and no longer uses an HTML file or creates an HTML backup for the bookmarks.<br /> There are 10 rotating daily JSON backups (bookmarks-####-##-##.json) in the bookmarkbackups folder within the Firefox profile folder, one for each day that Firefox is started. You can use this button to go to the Firefox profile folder: *Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder) *http://kb.mozillazine.org/Profile_folder_-_Firefox You can export the bookmarks in Firefox to an HTML file: * Bookmarks > Show All Bookmarks > Import & Backup > Export HTML You can also create a JSON backup: * Bookmarks > Show All Bookmarks > Import & Backup > Backup * An HTML backup doesn't support tags and annotations, so if you want to preserve those then you need to use a JSON backup. * Restoring a JSON backup will replace all existing bookmarks, so existing bookmarks are lost. * Importing an HTML backup will merge the imported bookmarks with existing bookmarks, so you do not lose the bookmarks that you already have, but you may get duplicate bookmarks if some already exist. *http://kb.mozillazine.org/Backing_up_and_restoring_bookmarks_-_Firefox