Nagios Support Forum

The ll command outputs a long list with all my hosts. The files are owned by nagios:nagios, I think this is what expected.
The bc package is also installed : bc.i686 1.06.95-1.el6 @base
Trying another browser, I just noticed that I get graphs normally with all browsers (IE, Google Chrome), but not when using Mozilla Firefox. Thus the issue seems to be circumscribed to that browser. Any hint?

Hold shift while reloading the browser, and also right click and select reload, which will reload all of your javascript files. I'm betting it's using an old cached version of the javascript files.

Great! That has worked!