Error
I deployed a new server, after that installed NSClient++ 0.4.3 The process was simple, nothing new, install NSClient and copy nsclient.ini from other server where work that, and copy extra (not included in template) config in windows.cfg file from working server. I was little embrassed when see this message: Exception processing request: Request contained arguments (not currently allowed, check the allow arguments option). 
I tried version of 0.4.1 NSClient, but same symptomes.
Solution
In the nsclient.ini the part of this, can change “true” to “1”
[/settings/NRPE/server]
#allow arguments = true (original part)
allow arguments = 1
