BUG #6501: postgresql-9.1.3-1-linux.run does not install on 64bit system

The following bug has been logged on the website:

Bug reference:      6501
Logged by:          Thomas Pasch
Email address:      thomas.pasch@nuclos.de
PostgreSQL version: 9.1.3
Operating system:   Linux 64 (Ubuntu 11.10/oneiric)
Description:=20=20=20=20=20=20=20=20

When I try to install postgresql-9.1.3-1-linux.run on a 64bit Linux, the
installer shows an error alert box and refuses to proceed.

This is strange because there are very few linux 64bit system that are not
able to run 32bit applications (and Ubuntu is even multiarch).=20

It would be ok if the installer issues a warning - but refusing the install
outright feels strange...=20