Configuration nagios

Bonjour à tous, j'installe nagios mais j'ai apparemmant un probleme de configuration. Si quelqu'un peut m'aider sa serrai vraiment gentil.

Lorsque je tape la commande suivente voici ce qui s'affiche:
#root@joseph-laptop:/usr/local/nagios/etc# /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

Nagios Core 3.2.1
Copyright (c) 2009-2010 Nagios Core Development Team and Community Contributors
Copyright (c) 1999-2009 Ethan Galstad
Last Modified: 03-09-2010
License: GPL

Website: https://www.nagios.org/
Reading configuration data...
Error: Cannot open main configuration file '/usr/local/nagios/etc/nagios.cfg' for reading!
Error processing main config file!

***> One or more problems was encountered while processing the config files...

Check your configuration file(s) to ensure that they contain valid
directives and data defintions. If you are upgrading from a previous
version of Nagios, you should be aware that some variables/definitions
may have been removed or modified in this version. Make sure to read
the HTML documentation regarding the config files, as well as the
'Whats New' section to find out what has changed.

Et quand je fait: #root@joseph-laptop:/usr/local/nagios/bin# ./nagios /usr/local/nagios/etc/nagios.cfg

Nagios Core 3.2.1
Copyright (c) 2009-2010 Nagios Core Development Team and Community Contributors
Copyright (c) 1999-2009 Ethan Galstad
Last Modified: 03-09-2010
License: GPL

Website: https://www.nagios.org/
Error: Cannot open main configuration file '/usr/local/nagios/etc/nagios.cfg' for reading!
Warning: Could not get passwd entry for 'nagios '
Warning: Cannot open log file '/usr/local/nagios/var/nagios.log' for writing
Nagios 3.2.1 starting... (PID=5636)
Warning: Cannot open log file '/usr/local/nagios/var/nagios.log' for writing
Local time is Fri Jun 18 16:16:35 CET 2010
Warning: Cannot open log file '/usr/local/nagios/var/nagios.log' for writing
Warning: Cannot open log file '/usr/local/nagios/var/nagios.log' for writing
Bailing out due to one or more errors encountered in the configuration files. Run Nagios from the command line with the -v option to verify your config before restarting. (PID=5636)

AIDER MOI SVP...