A commonly reported issue with NSClient++ is seeing the following error when trying to install the service or run the client:
“The image file c:\[Path]\nsclient++.exe is valid, but is for a machine type other than the current machine”
The cause of this issue is attempting to run the incorrect version of the client for your architecture i.e. Trying to run the 64-bit version on a 32-bit operating system. The solution, obviously, is to run the correct version.