"Failed to send snapshot to the Report Service : No response from the Report Service at this URL."
This is a common error when first using Essential and is typically the result of Tomcat not running.
Try visiting http://localhost:8080 and see if you are able to view the standard Tomcat page?
If not, then try starting Tomcat via the system tray icon (if present) or via the [Tomcat install]/bin/startup.bat or startup.sh file.
Finally, check that you have properly installed Essential Viewer? i.e. if you visit http://localhost:8080/essential_viewer do you see the standard Essential Viewer homepage?