Problem in offline backup & restore

C:\[path to pg_restore.exe ]\pg_restore.exe -i -h localhost -p 5432 -U postgres -d mydb -c -v C:\MyBackups\db_backup.backup

The above 2 commands working perfect while database is online (running).

However the problem is they are not working while database is offline (database shutdown)

It is showing the following error message:

pg_dump: [archiver (db)] connection to database "mydb" failed: could not connect
to server: Connection refused (0x0000274D/10061)
        Is the server running on host "localhost" and accepting
        TCP/IP connections on port 5432?
pg_dump: *** aborted because of error

Is it possible to backup & restore the database offline? If so what is the problem in my command.

Please help me.

Thanks

Sreeman