DMX-Workshop is the free-of-charge Windows application for monitoring and configuring Art-Net devices. When used with Windows 7 (as opposed to Windows XP), certain additional steps are required to ensure it runs correctly.
On your computer, locate the installation directory for DMX-Workshop and right click on the .exe (you can also right click on the desktop shortcut). A menu will appear. Select Properties. Select the Compatibility Tab. Select Windows XP Service Pack 3.
Display settings will vary depending on the computer. First try running with no display settings selected. If there is a display problem try disabling the bottom 3 options and running in 256 colours.
Running in compatibility mode should allow you to run all Artistic Licence programs that are specified for Windows XP on a Vista or Windows 7 computer.