An error in your system configuration has been detected
General installation instructions can be found
here.
For more specific hints on the existing issues please have a look at the messages below. 
It looks like the __CA_URL_ROOT__ variable in your setup.php is not set correctly. Please try to set it to "/frontend". We came up with this suggestion because you accessed this script via "<your_hostname>/frontend/index.php". Note that paths are case sensitive.