[The Slider]has some error

There is error :

Fatal error: Call to undefined function get_the_post_thumbnail() in C:\xampp\htdocs\—-\wp-content\plugins\the-slider\the-slider.php on line 188

i using the-slider in index.php so i using
<?php the_slider(array(“cat” => 3,”max” => 4)); ?>

so i post 4 picture (1 post ,1 picture ) with category ID = 3.

http://wordpress.org/extend/plugins/the-slider/