stuck with libc6 upgrade

[Werner Reisberger <werner@pure.ch>]

I am running an original  hamm system but upgraded to libc6 (v 2.1.1) and 
kernel 2.2.10. 

I ran "apt-get update" to potato succesfully. When I try 

  apt-get install libc6

the error message 

   (Reading database ... 6883 files and directories currently installed.)
   Preparing to replace libc6 2.1.1-3 (using .../libc6_2.1.3-5_i386.deb) ...
   dirname: too many arguments
   Try `dirname --help' for more information.
   pushd: not found
   dpkg: error processing /var/cache/apt/archives/libc6_2.1.3-5_i386.deb
   (--unpack):
    subprocess pre-installation script returned error exit status 127
   Errors were encountered while processing:
    /var/cache/apt/archives/libc6_2.1.3-5_i386.deb
   E: Sub-process returned an error code (1)
   
occurs.

Any help appreciated since I urgently need to install some packages which
depends on libc6 >= 2.1.2

Werner