If I right click on the icon and click the "Hide whe minimized" option nothing happens (the option appears to be greyed out).
I found this in Vista Help (it seems the only option is to uninstall Eraser which is not what I want).
Remove icons from the notification area (system tray)
The notification area is located on the taskbar and contains program icons that provide status and notifications about things like incoming e‑mail, updates, and network connectivity. When you install a new program, you can sometimes add an icon for that program to the notification area.
New computers often come with icons already in the notification area, and some programs automatically add an icon to the notification area during installation.
To remove an icon from the notification area
Right-click the icon, and then click Exit.
Depending on the program, the menu item you need to click to remove the icon might be different (for example, Quit or Close instead of Exit).
If you remove an icon, but then see it again the next time you log on to Windows, you might have to uninstall the program to permanently remove the icon. Uninstalling the program also permanently removes the program from your computer. For more information, see Uninstall or change a program.