problema al instalar metaexploit

[xemnas]

cuando esta mas o menos al 30% me salta este error
There has been an error.
Error running su postgres -c '"/opt/framework-3.5.1/postgresql/bin/psql"  -c "ALTER USER postgres PASSWORD '\''cdb4625f'\''" ' : psql.bin: could not connect to server: Connection refused
   Is the server running on host "localhost" and accepting
   TCP/IP connections on port 7175?
could not connect to server: Connection refused
   Is the server running on host "localhost" and accepting
   TCP/IP connections on port 7175?
The application will exit now.

gracias de antemano