I am attempting to convert an application which is running Silverlight.
I didn't actually know which version of Silverlight the application was built with until i found this:
<param name="minRuntimeVersion" value="3.0.50106.0" />
So i've then assumed i need to upgrade from Silverlight 3 to Silverlight 4.
Assuming you have Visual Studio 2010 installed, you should have Silverlight 4 and the Silverlight 4 SDK installed.
Ensure your projects are targetting the .Net 4 Framework and Silverlight 4.
You can find this out by right clicking on each Project in your solution and choose Properties. If it is a Silverlight project, you'll see 'Target Silverlight Version'. Otherwise you should find 'Target Framework'.