Error trying to install postgresql-server

I am trying to use postgresql on my server, since sqlite databases don't seem to work at all and I want to get Trac running.

I'm on a Virtuozzo VPS with CentOS 5 (fully up to date).

So anyway, I am getting a scriptlet error when trying to install postgresql-server-1.1.11 with yum. Here are the full results:

Code:

=============================================================================
 Package                 Arch       Version          Repository        Size
=============================================================================
Installing:
 postgresql-server       i386       8.1.11-1.el5_1.1  updates           3.9 M

Transaction Summary
=============================================================================
Install      1 Package(s)
Update       0 Package(s)
Remove       0 Package(s)

Total download size: 3.9 M
Is this ok [y/N]: y
Downloading Packages:
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
error:   install: %pre scriptlet failed (2), skipping postgresql-server-8.1.11-1.el5_1.1

Installed: postgresql-server.i386 0:8.1.11-1.el5_1.1
Complete!

UPDATE: By the way, same result with /scripts/installpostgres... The script for some reason thinks it was successful but it skips with the same error.