try again from : http://www.mozilla.org/en-US/firefox/all.html thank you

It is possible that your anti-virus software is corrupting the downloaded files or otherwise interfering with downloading files by Firefox.<br /> Try to disable the real-time (live) scanning of files in your anti-virus software temporarily to see if that makes downloading work. See "Disable virus scanning in Firefox preferences - Windows" *http://kb.mozillazine.org/Unable_to_save_or_download_files