How to install dpkg-reconfigure?
Solution 1:
dpkg-reconfigure is provided by the debconf package, which should always be installed in any Ubuntu 12.04 install. If it's not, use:
sudo apt-get install debconf
In your case, you are running Amazon's AMI Linux which is based on CentOS, not Ubuntu. That's why apt-get or dpkg-reconfgure, which are native to Debian/Ubuntu, are not available on your EC2 instance.
Solution 2:
Normally it's already installed in Ubuntu. But if you are using some customized version without dpkg, you should be able to install using the command
sudo apt-get install dpkg