How I re-installed network manager in ubuntu offline

I've got an error when I tried to install network-manager from ubuntu liveCD, So I downloaded the package network-manager-gnome package to another computer and installed to mine. After that I used liveCD to install the network-manager package.

• sudo apt-cdrom add
   
• gksudo gedit /etc/apt/sources.list
   
  Uncomment the line
  # deb cdrom:[Ubuntu 12.04 LTS _Precise Pangolin_ - Release i386 (20120423)]/ precise main restricted
  by removing # symbol
   
• sudo apt-get install network-manager