That bug has been opened on https://launchpad.net/distros/ubuntu/+source/gnome-terminal/+bug/36285

"In gnome-terminal:

  echo ftp://ftp.gag.com/debian/

Right-Click "Open Link". This FTP server exists but currently has anonymous access disabled, because of the Login incorrect message, gnome-terminal's builtin(!?) FTP client goes into an infinite loop with the terminal not being updatable and 'kill -9' the only solution.

  connect(23, {sa_family=AF_INET, sin_port=htons(21), sin_addr=inet_addr("192.133.104.8")}, 16) = 0
  read(23, "220 ProFTPD 1.2.10 Server (Debia"..., 4096) = 52
  write(23, "USER anonymous\r\n", 16) = 16
  read(23, "331 Password required for anonym"..., 4096) = 38
  write(23, "PASS nobody@gnome.org\r\n", 23) = 23
  read(23, "530 Login incorrect.\r\n", 4096) = 22
  close(23)

Please email 'bdale@gag.com' so he can re-enable his FTP server after this is tracked down.

http://librarian.launchpad.net/1822538/gnome-terminal-anonymous-ftp-bzzzt.strace.txt
result of:

  strace -p `pidof gnome-terminal`
...
I don't know how to mark this as confirmed, but I can confirm this. I tried it with my server which also has no anonymous access.
...
If this can't be tracked down, I guess just disabling FTP URLs from within gnome-terminal might be a hack to stop it happening."