Plugin activation error with PHP version lower than 5.3.0

Since one of my client server is running PHP 5.2.9
When I turn this plugin on, error is occured due to
__DIR__ is added since 5.3.0

So, I suggest you the following way to be the path instead:
plugin_dir_path(__FILE__)

because magical constant __FILE__ is added since PHP 4.0.2
ref: http://www.php.net/manual/en/language.constants.predefined.php

Many thanks

http://wordpress.org/plugins/scriblio-authority/