Header.ssi not displayed

Hi there,
Im a newbie in the world of Nagios so please be patient!

According to what I have read, the common-header.ssi and common-footer.ssi should be picked up by the web front-end, however they do not seem to be displayed, Could somebody please point me in the right direction as to where this is set?

Many thanks
Steve

nagios.sourceforge.net/docs/3_0/cgiincludes.html
Have you done everything that is explained in the above documentation?

Yep, using global header/footer, i.e.:
common-header.ssi:
Back to main Nagios screen

I am also getting a random question mark image on the right which links to contexthelp.

Steve