In version 0.19.4(and a few earlier versions) there is a typo in the spec file:
--- obs/dnx.spec.in.orig 2009-10-05 12:04:40.664563000 -0400
+++ obs/dnx.spec.in 2009-10-05 12:05:00.145067000 -0400
@@ -157,7 +157,7 @@
%doc doc/%{name}-doxy-%{version}.tar.gz
%files server
-%defattr(0644,%{nagiosusr},%{nagiosgroup})
+%defattr(0644,%{nagiosuser},%{nagiosgroup})
%config(noreplace) /etc/nagios/dnxServer.cfg
%{_libdir}/nagios/brokers/dnxServer.so
%{_libdir}/nagios/plugins/sync_plugins.pl