You access instances through the hostname that you assign to the instance. So, make sure that the name that you gave to that instance resolves to the computer in question - e.g. localhost. This might involve an entrance in your etc/hosts file (location depending on your operating system)
On a related note: Please collect some karma by crossreferencing all the places on the web where you asked the same question. If someone has answered the question there already, we can save the same work at all of the other places. Thanks.
There's no inherent problem with crossposting in different places - just link all of them to each other. In general it's better to get along without crossposting though.
