E: Sub-process /usr/bin/dpkg returned an error code (100)

Go to http://archive.ubuntu.com/ubuntu/pool/main/d/dpkg/ to download the package you need.

mkdir /tmp/dpkg
cd /tmp/dpkg
wget http://archive.ubuntu.com/ubuntu/pool/main/d/dpkg/dpkg_1.15.5.6ubuntu4_i386.deb
ar x dpkg*.deb data.tar.gz
tar xfvz data.tar.gz ./usr/bin/dpkg
sudo cp ./usr/bin/dpkg /usr/bin/
sudo apt-get update
sudo apt-get install --reinstall dpkg