Your system says it has dpkg 1.18 installed as it should, but somehow it appears that your dpkg-maintscript-helper program is from an older version. You might be able to fix it by running apt-get install --reinstall dpkg.
Your system says it has dpkg 1.18 installed as it should, but somehow it appears that your dpkg-maintscrip t-helper program is from an older version. You might be able to fix it by running apt-get install --reinstall dpkg.