LinuxQuestions.org - PAM & chfn failure

I'm trying to install logcheck, and this is what happens. I'm also confused as to why for some package installs it asks for root password even if I'm already logged in as root.

Code:

root@Kate:~# apt-get install logcheck

Reading package lists... Done

Building dependency tree       

Reading state information... Done

The following NEW packages will be installed:

  logcheck

0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.

Need to get 0 B/77.3 kB of archives.

After this operation, 156 kB of additional disk space will be used.

Selecting previously deselected package logcheck.

(Reading database ... 219524 files and directories currently installed.)

Unpacking logcheck (from .../logcheck_1.3.13_all.deb) ...

Processing triggers for man-db ...

Setting up logcheck (1.3.13) ...

Password: 

chfn: PAM authentication failed

dpkg: error processing logcheck (--configure):

 subprocess installed post-installation script returned error exit status 1

configured to not write apport reports

                                      Errors were encountered while processing:

 logcheck

E: Sub-process /usr/bin/dpkg returned an error code (1)