I am using the 30-day trial, and noticed that my NetMaster is just sitting there: no network activity is displayed and all buttons except "connect to a remote computer" are inactive (and I hadn't even installed the remote connection module).
It sounds like you have only installed the Management Console (GUI), without the System Service required for normal operation.
NetMaster consists of two major components: the System Service that does all the monitoring work, and the Management Console that enables you to interact with the service. During the installation you can choose which components to install, and normally you would need both to get started. Please have a look at our brief user manual for more details.
In more complex cases, when you have several computers and want to use just one of them for management, you would need to install the System Service on all computers you want to monitor/manage, and the Management Console (with or without the System Service) on the computer you want to use for management. The computers without the System Service will not have their own traffic monitored. This offers a great flexibility in the management arrangement, and this is why the choice of components is offered during the installation.
Additionally, you can choose to install the Taskbar Extension, which will let you have a small widget in the notification area to keep an eye on your downloads and uploads.