in the webpage.php file in application\layouts on line 19 the code is:
echo stylesheet_tag('custom.css');
There is no custom.css file. I was getting errors in my Apache log file on this.
In my particular case I have OpenGoo running under SSL and the error was basically removing the security since I was calling a custom error file using http. If you run OpenGoo using SSL and the SSL is broken after navigating off the login page there are two ways to correct this:
1. Add an empty file custom.css in public\assets\themes\default\stylesheets
2. Add a custom error file directive (ErrorDocument 404) in your SSL configuration