After Installing Debian 7 at Network Connections VPN add button is Disable.
After long search for the missing packages, I reinstall Debian 7.4 and install the next 3 packages, found in the link HERE.
sudo apt-get install network-manager-pptp
sudo apt-get install network-manager-pptp-gnome
sudo apt-get install pptp-linux
VPN Add Button become enable.
To support OpenVPN and be able to open “.ovpn” files install the followin packages:
sudo apt-get install openvpn network-manager-openvpn network-manager-openvpn-gnome
Reference link HERE.