I receive the same error of it being insecure.

Go to "I understand the risks"

Click add exception and then hit "Confirm Security Exception"

Thanks for the help. However, I did that and then did get to a server but with the response Port 443 NOT FOUND

That means the file is no longer on the server I received the same error oo so don't fear :D

Could the problem be with COMCAST? I recently received a new Modem/Wifi. I don't think I configured FireFTP correctly. I don't know my host name or user name or password.

any suggestions?

Did you try to run the FTP program via a command prompt window on Windows or a terminal window on Linux to see any error messages?

Open a cmd.exe command line window and execute these commands:

ftp
open ftp.mozilla.org
username: anonymous
password: anonymous
cd pub/mozilla.org/firefox/releases/latest/win32/en-US
ls
binary
lcd ~\Desktop (save the file to the Desktop)
get "Firefox Setup xx.0.exe" (make sure to use the quotes)
(verify that you have the Firefox Setup xx.0.exe file on the USB drive)
bye

Thanks for the input Cor-el.

Here is what I got on my Ubuntu terminal:

lew@lew-VirtualBox:~$ ftp ftp> open ftp.moxilla.org ftp: connect: Connection timed out ftp>

I have also tried to download from the Harvard Chandra site(something I have done a number of times earlier this year) and got

lew@lew-VirtualBox:~/CIAOstuff$ download_chandra_obsid 1842

1. download_chandra_obsid (06 August 2013): ERROR [Errno 110] Connection timed out

lew@lew-VirtualBox:~/CIAOstuff$ download_chandra_obsid 1838 evt2

1. download_chandra_obsid (06 August 2013): ERROR [Errno 110] Connection timed out

Any suggestions?

 ftp: connect: Connection timed out

You're putting moxilla.org instead of mozilla.org.
Replace the x with the z

 Then tried https://sao-ftp.cfa.harvard.edu/pub/transfer/nlee/acis_bkgrnd_4.5.7.tar.gz Got windows warning of unsecure server; requested over ride. Then got message from hea-www.harvard Port 443 NOT FOUND

I simply had to add an exception to get to it but it seems like whatever file you were trying to download isn't available anymore. Since it's on the Harvard network, I would suggest you ask IT at the Harvard campus to see if there are other ways to download that file if you truly need it. More info: I can't even navigate to http://sao-ftp.cfa.harvard.edu/pub without getting 404'd (probably needs a user/password combo internally)

PROBLEM SOLVED Problem was with COMCAST router firewall. Their tech support fixed it in 5 minutes after my third try with them.

Thanks for all your help. Lew