Try this https://support.mozilla.org/en-US/kb/rebuilding-global-database to answer what is in the images. As for the actual words, you probably have an an over active firewall or antivirus product installed. But why are you trying to download it? I appear to be already installed. Reinstalling is almost guaranteed not to fix anything. It is about the last thing anyone in this forum would recommend for most issues related to getting mail or sending mail. It can work for operating system integration issues. But not for mail issues on existing accounts. The settings for which are totally unaffected by reinstalling.