ftp://ftp.mozilla.org:21/pub/firefox/releases/3.6.28/win32/en-US/Firefox Setup 3.6.28.exe - the 'raw' download link copied from my FTP client (FTP Rush)

ftp://ftp.mozilla.org/pub/firefox/releases/3.6.28/win32/en-US/Firefox Setup 3.6.28.exe - the download link processed by my download manager (Free Download Manager)