Sorry for the delay guys. I'm going by memory here since I'm not at my DAW.
After you install the Faderport files, the DLL file can be found in "C:\Program Files\PreSonus\FaderPort\FaderPort Dll". Copy Faderport.DLL file to the "C:\Program Files\Cakewalk\Shared Surfaces" folder.
Make sure Sonar is closed, and then invoke the Run Command by using the Windows key and and "R" key. Then type:
regsvr32 "C:\Program Files\Cakewalk\Shared Surfaces\faderport.dll"
Finally, you'll click OK and you'll see a message that confirms the DllRegisterServer was successful.
Now you can go through the normal steps In Sonar to add the Faderport MIDI ports and control surface. The manual in the latest Presonus FaderPort download includes a section that is dedicated to a Sonar installation.