The server doesn't accept the current user: The server reports
If this message appears, the pg_hba.conf entry found for your client / user / database combination is set to "ident" authentication. Some distributions, e.g. Debian, have this by default. To perform ident based authentication successfully, you need additional setup; see the PostgreSQL help for this. For a beginner, it might be more appropriate to use a different authentication method; MD5 encrypted passwords are a good choice, which can be configured by an entry in pg_hba.conf like this:
host all all 192.168.0.0/24 md5
This example grants MD5 encrypted password access to all databases to all users on the private network 192.168.0.0/24.
You can use the pg_hba.conf editor that is built into pgAdmin III to edit the pg_hba.conf configuration file. After changing pg_hba.conf, you need to trigger a server configuration reload using pg_ctl or by stopping and restarting the server process.