BUG #3290: can't install

The following bug has been logged online:

Bug reference:      3290
Logged by:          Indrek
Email address:      indrek.mail@mail.ee
PostgreSQL version: 8.1.9-1
Operating system:   Windows XP
Description:        can't install
Details:

I have downloaded this file: postgresql-8.1.9-1.zip
But I can't install it, because there is first this error message: Please
use main MSI file to install PostgreSql
And after this message there is another one:

Installation ended prematurely because of an error.

Which error it is, I don't know, because there is no information about it.

What is problem?