QUESTION:

Warning: mysql_connect(): Client does not support authentication protocol requested by server; consider upgrading MySQL client in /Library/WebServer/Documents/tp1/textpattern/setup/index.php on line 187



ANSWER:

This and similar errors are caused by a PHP installation problem: the version of the PHP mysql client library is older than the MySQL server.

You should raise a support ticket with your web hosting company, and ask them to reinstall the correct versions.