Logon respective server's WHM and follow the below mentioned steps

1. Software > Install an RPM > PostgreSQL > install

2. Software > Install an RPM > PostgreSQL-server > install

3. Restart Services > Postgresql Server

4. Service Configuration > Postgres Config > Enter New Password

5. Service Configuration > Postgres Config > Install Config

Installation complete.

Also please refer url http://forums.cpanel.net/showthread.php?t=...issing+postgres