Thanks luca for your time and patience with this. I read that link, and yes it is the very same problem as described. The interesting bit was the permissions bit and the results from running the grep command;
grep authori cgi.cfg | grep -v '#'
That is exactly the results that come up when I run it. Um, is this possibly the reason for the errors? Do I need to alter those to point to nagios?
Also my default webserver doc root is not /var/www/ but /home would this make any difference? As the initial nagios home page displays I wouldnt have thought so.
It must be a permissions problem with the cgi's. Have I got my nagios nagiosadmin and www-data users and groups set right I am wondering?
My users&groups are:
user nagios - 1004
group nagios - 1004 linked to groups www-data & nagios
group nagcmd - 1005