Whoops! Error: Could not read object configuration data!

Hi all,
We are trying to install nagios 2.x and the main page of the web works correctly, but it gives an error when try to configure the Object Configuration File and the Object Configuration Data.
Can you please help us?
Thank you!

Hi !
have you tried to run the CFG check ?
( nagios_install_dir/bin/nagios -v nagios_install_dir/etc/nagios.cfg ) ?