It's a good idea to first make sure that your web server meets the minimum requirements to run TubePress. The only critical requirements are that you are using PHP 5.3.29 or higher and that you are not running the APC extension.
Additionally, if you intend to use TubePress in any language other than English, TubePress requires the PHP Multibyte String extension (enabled by default in most PHP installations).
Not sure if your server meets this requirement? You should either:
File > Savefrom your web browser's menu, or just hit
Ctrl-S). It should be saved somewhere on your local machine, and the name of the file should be
check.phpto your website's document root.
http://<yourdomain.com>/check.php. The output of this page should be self-explanatory and will look similar to the following: