Comment 5 for bug 593615

I've just had this bug on Ubuntu 11.04. It stopped me from adding or removing packages because it couldn't find a group 'cdemu' which is carzy. I added the group using 'addgroup cdemu' and ran 'apt-get purge cdemu-client' deleted the group with 'delgroup cdemu' and was still stuck because it hadn't purged the reference to the cdemu group. So I found the name of the associated file 'vim /var/lib/dpkg/statoverride' in my case it was '/usr/bin/cdemud' and got rid of it with 'dpkg-statoverride --remove /usr/bin/cdemud'.