The source code uses SerialDevice.dll / SerialDesktop.dll libraries.
These libraries are only supported on .Net CF 1.0.
WM6.0 devices are installed with .Net CF 2.0.
The Serial2 library is supported by .Net CF 2.0.
Using Tools - Components, you should remove these two libraries and add Serial2.dll to the device and desktop.
See this page for more information about .Net CF 1.0/2.0:
www.basic4ppc.com/netcf2.html