Install question

Hello.

I'm trying to install PostgreSQL 8.1.4 in a XP SP2 machine and I get the following errors:

1.) "Failed to connect to the database. Procedural language files are installed, but are not activated in any database."

 ----> I click OK and the installation proceeeded a little further...

2.) "server closed the connection unexpectedly. This probably means the server terminated abnormally before or while processing the request"

----->Clicked OK again....

3.) "Failed to connect to the 'template1' database. Contrib files are installed, but are not activated in any databases."

Can someone tell me what are the possible reasons for this to happen?

Thanks!