Hi, did you manage to solve this error, I'm seeing exactly the same.
Not really. I tried changing the nagios_nrpecheck to use the "old style" notification syntax recommended here: http://www.sharp-tools.net/archives/002187.html
Then this error seemed to happen less, but still happened sometimes. (I don't recall the particular conditions.)
Eventually I just stopped using the nagios_nrpecheck provider altogether; and wrote my own templates that notify nagios-nrpe-server.
yeah, I tried that fix too :-(