The error message says that the server connection could not be established, which may have several reasons, e.g. the server was temporarily down, when you tried to download the terrain model. I rather think that you have some firewall issues or administration settings blocking the connection.
Unfortunately, tutorials and documenations are still in working progress but will be released within the next weeks. There will be a webinar on Performance Network as well.
ENVI-met Monde World Editor (BETA)