Okay, lets start over. Your original post said.
Append the text below to your constants.conf file on your Windows host and restart the Icinga2 service on your Windows host. This has resolved this error for me on my Windows host.
/* The directory contains the local NSClient++ plugins
* This resolved error - scp.exe, The system cannot find the file specified.
*/
const NscpPath = "C:\\Program Files\\NSClient++"