Thanks for getting back to me.
I noticed that myself after I downloaded the source.
In the end I got it to work after a bit of hacking at the code.
After removing the projects I didn’t need from the solution I rebuilt the Dlls for the 2.0 framework, which got past the System.Configuration problem.
It then threw another exception (of which I can’t remember the exact name) related to NLog.dll. As a temporary solution I removed all calls to the logger from the code.
There were no other problems after that and the networking code works perfectly in Unity’s WebPlayer.