[ADMIN] Intallation of postgres 9.0.3 gives an error on already installed postgres 8.4 on the same machine

[Prabhjot S. Sheena]

I have postgres 8.4 already installed on my machine

Now I am trying to install 9.0.3 on the same machine

But when I am trying to run rpm -ivh  postgresql90-9.0.3-1PGDG.rhel5.x86_64.rpm 
       it gives me the following error:

error: Failed dependencies:
        postgresql < 7.4 conflicts with 
postgresql-server-8.4.6-1PGDG.rhel5.x86_64


Can anyone help with this .....

Thanks