Problems installing 9.2 on Ubuntu 12.04

Hi,

I am trying to install postgresql-9.2 using the instructions in the apt
wiki. I already have 9.1 installed - and would like to keep both for the
moment - but the install of 9.2 fails as below...

  sudo apt-get install postgresql-9.2
Reading package lists... Done
Building dependency tree
Reading state information... Done
postgresql-9.2 is already the newest version.
The following packages were automatically installed and are no longer
required:
   linux-headers-3.2.0-44-generic linux-headers-3.2.0-41
linux-headers-3.2.0-36
   linux-headers-3.2.0-43 linux-headers-3.2.0-44
linux-image-3.2.0-43-generic
   linux-headers-3.2.0-43-generic linux-image-3.2.0-41-generic
   linux-image-3.2.0-44-generic linux-headers-3.2.0-41-generic
   linux-headers-3.2.0-36-generic
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 111 not upgraded.
3 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue [Y/n]? y
Setting up postgresql-client-9.2 (9.2.4-1.pgdg12.4+1) ...
update-alternatives: error: alternative pg_basebackup.1.gz can't be
slave of psql.1.gz: it is a slave of postmaster.1.gz
dpkg: error processing postgresql-client-9.2 (--configure):
  subprocess installed post-installation script returned error exit status 2
dpkg: dependency problems prevent configuration of postgresql-9.2:
  postgresql-9.2 depends on postgresql-client-9.2; however:
   Package postgresql-client-9.2 is not configured yet.
dpkg: error processing postgresql-9.2 (--configure):
  dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of postgresql:
  postgresql depends on postgresql-9.2; however:
   Package postgresql-9.2 is not configured yet.
dpkg: error processing postgresql (--configure):
  dependency problems - leaving unconfigured
No apport report written because the error message indicates it's a
follow-up error from a previous failure.
                             No apport report written because the error
message indicates it's a follow-up error from a previous failure.
                                                         Errors were
encountered while processing:
  postgresql-client-9.2
  postgresql-9.2
  postgresql
E: Sub-process /usr/bin/dpkg returned an error code (1)
server9:~$

What can I do to fix?

Thanks.