As I recall, it IS possible to run 2 different instances of VWS on 2 different stations at one time. I did it once, with a little help from Ed. You at least have to install the second one to a different folder/directory than the first. I'm trying to remember if there was some registry magic involved as well.
Ah, good ol' Google... here it is...
https://ambientweather.wikispaces.com/Running+more+then+one+instance+of+Virtual+Weather+Station+on+the+same+computerProblem
I would like to run more then one instance of Virtual Weather Station on the same computer. Virtual Weather Station will not allow me to install two instances of VWS on the same computer.
Solution
Install Virtual Weather Station as normal. This is your first instance.
Copy the entire vws directory to a different location (your choice).
Launch the new instance of Virtual Weather Station. Select Settings | Multiple Station Settings and select Recall Existing Station. Browse to the new directory location on the new computer. For example, if you install it into the c:\vws2 drive, browse to the c:\vws2 drive.
There are several customized file paths you will need to change in the new instance of Virtual Weather Station. Select the following windows from the menubar and change to valid directory locations.
Settings | CSV Export
Settings | Jpeg File Settings
Settings | WeatherVoice
Settings | WeatherCentral Settings
Internet | HTML Settings
Internet | Upload File
Internet | Upload Folder