how about for a mac?

Unable to login to database (postgres). Reason: could not connect to server: No such file or directory Is the server running locally and accepting connections on Unix domain socket "/tmp/.s.PGSQL.5432"?'

this is the error message

After using PT4 for about a month on trial, I was unsure what this postgres business was so I unwittingly deleted it. Now I am unable to run my PT4 and have tried to uninstall/reinstall and keep getting same error message? How do I resolve this and reestablish postgres?

Thank you