I've installed PHP-CA a few times I love the functionality, but the error handling during the setup process needs improvement. From a UI prespective, the install process should not even display the form for the CA until it has checked that it has permissions to create it.
Also, the file openssl/crypto/serial always generates a file not found message for me, unless I create it before...
The issue is almost certainly permissions. PHP-CA needs a better explanation of the permissions requirements. I know it needs to be able to write to certain subdirectories of itself. The setup process should check those permissions and tell you which ones need changing, but it doesn't at the moment.
