Help with Agile Carousel Plugin

Can anyone help me? I am receiving this error:
Fatal error: Call to undefined function: filter_var() in /home/
my_webserver_path/ufal/make_slides.php on line 17
when I try to use the example posted from this demo:
http://www.5bosses.com/examples/agile_carousel/full_example/carousel.html
What am I doing wrong?
Vince--