When you say "I downloaded MS Visual Studio just to unsandbox the program", I'm a little usure what it is you're trying to do? On my site I use the term 'Sandbox' to refer to a Silverlight application that is running in the browser window. There are security restrictions in place that restrict a browser-based application from accessing local resources on your computer e.g. serial ports. To 'unsandbox' a Silverlight applicaiton means to have it run locally on your computer - not on a web page. A Silverlight application running Out-of-Browser can be granted 'elevated trust' enabling it to access certain local resources on your computer. In the case of the Arduino Firmata Tester that is access to the local 'port' provided by a serial proxy application (what I believe you are referring to by 'serial redirector').
To run a Silverlight application Out-of-Browser, to 'unsandbox' it, you do not need MS Visual Studio. You simply 'install' the application from the web page where you found it. The Arduino Firmata Tester look like this:
And it can be found here: http://yuleblinker.com/silverlight_arduino/installation.html
To use the Arduino Firmata Tester from the site you do not need MS Visual Studio. You need to install it from the page and have a 'serial proxy' application configured and running on your computer. And, by the way, you also need to upload the StandardFirmata sketch onto your Arduino board (I'm assuming you've done that!
I have provided all the code that was used to create the Arduino Firmata Tester Silverlight application in the form of a Visual Studio project folder. This is the 'raw' code and assests. It is available as zipped download from the Links page: http://yuleblinker.com/silverlight_arduino/links.html
. It is this project that you can open in Visual Studio. When I mentioned above that you can change the Properties for the project it is when you have it open in MS Visual Studio. You only need to open this project in Visual Studio to investigate how it was created or to change or amend it.
When you say 'the program connects but fails to do anything else', what do you mean? For it to do something you will need to have something connected to your Arduino board - LEDs, buttons, potentiometers etc. When you connect the application try clicking the Firmware, Capabilities and Pin Values buttons. Each of these should at least trigger a response from the board if it is indeed connected and running Firmata.