A .htaccess file and php.ini file are supplied in the distribution. It may be advisable to check if same-named files already exist on the server, and whether over-writing them would cause any issues.
This usually indicates that there is a line in the .htaccess file which the server cannot understand. It might also indicate that a setting is present in .htaccess or php.ini which the hosting company has disallowed.
If your php implementation is the CGI variety and the 'php_value auto_prepend_file' .htaccess line is activated, you will most definitely get this message. The fix is to add # to disable this line.
The respective line in php.ini or .htaccess refers to an incorrect location, or the file is missing. This might also arise if the permissions on the codebase directory are incorrect.
Ensure that you are viewing the site through the webserver, and not by opening the pages directly from the zip. Regardless of the CMS used, no php site can be viewed directly from its files. The other reason this may happen is if the Mara system is not being launched, and what you are seeing is the bare page content. It may be that the server's php setup is configured to disallow prepending, or that the php version is too old. Or, the page may be missing the 'shebang' (reflex loader command) in its first line.
A yellow 'theme missing' message appears, followed by the plain page content.
This indicates that either some files are missing from the theme, or that the reference to the theme in siteini.php is pointing to an incorrect location. For example if the theme declared in siteini.php is slate then the theme's files should be in theme/slate