I had this too when upgrading from 1.0.1 to hardy-unstable, when I got the error message I rolled back, removed the manpages package and then tried again. This then succeeded and afterwards I installed manpages again with no trouble.
I had this too when upgrading from 1.0.1 to hardy-unstable, when I got the error message I rolled back, removed the manpages package and then tried again. This then succeeded and afterwards I installed manpages again with no trouble.