The server configuration requirements are:
PHP 5.3.3 or later. We recommend using PHP 7.0 or 7.1.
PHP zlib module installed and enabled. This should be enabled by default.
Correct directory and file ownerships and permissions, or FTP connection parameters must be entered.
The last requirement must be further explained. PHP with Safe Mode enabled will refuse to create folders inside another folder which is not owned by the same user as the one the web server (Apache) runs under, even if the folder is otherwise writable. Kickstart will fail in this case. Alternatively, if you supply the FTP connection information, Kickstart will try to use FTP to connect to your site and write the extracted files.
If you use the FTP mode, Kickstart will require the specified temporary directory to be directly writable by PHP (usually, 0777 permissions help) or it will attempt to create a temporary directory of its own. If this procedure fails, Kickstart will notify you that the temporary directory is not writable.
Moreover, if you already have a site installed on the target server you have to ensure that all folders and files are writable. If not, Kickstart will fail and leave your site in a possibly broken state.