There are several reasons this error may occur:
-> PostgreSQL isn't running
-> PostgreSQL isn't listening for TCP/IP connections (listen_addresses in postgresql.conf)
-> PostgreSQL is listening on a different port to the one you're connecting on
1. First step is to verify PostgreSQL is running. A TOP should list the process. If not, you can also run a NETSTAT on default PostgreSQL port 5432 to see if the port is connecting.
If PostgreSQL is not running, you can start it using the available startservers.sh script:
<CABI INSTALL DIR>/startServers.sh
2. You can also verify default port 5432 is open by running NETSTAT -ano | grep -i 5432
3. Check local IP tables are turned off/disabled
4. Check external firewall rules for potential blocking port 5432
5. The address and port configuration are located in <CABI INSTALL DIR>/postgresql/data/postgresql.conf. Verify the port setting is correct.
6. Run a sniffer trace to check connection to PostgreSQL database