Before you install compatible version of Prestashop with your PHP version on server you need to this:
https://devdocs.prestashop.com/1.7/basics/installation/system-requirements/
Also you can use documentation for each version of prestashop from here
http://doc.prestashop.com/
Latest version is located for download here: https://www.prestashop.com/en/download?ab=1
When you have error:
it's a clear message that you are:
not properly configured server settings, (check your PHP settings on server) - read about it on link in previous post,
or your module is not for compatible with this prestashop version (only in case if you are uploaded module to store)
or your module is not for compatible with PHP version on server. (try to start module after you change PHP version (new/old))