[Plugin: WPPA] Fatal error: Call to undefined function esc_textarea()

Hi all,

I just downloaded the last version of WPPA, and it works very good… until you want to enlarge a picture by clicking on the thumb; then the screen turns white and I get the message:

Fatal error: Call to undefined function esc_textarea() in /home/guk/public_html/wp-content/plugins/wp-photo-album-plus/wppa-functions.php on line 1768

Which refers to
$result .= '<textarea name="wppa-comment" id="wppa-comment-'.$wppa['master_occur'].'" style="height:60px; width:100%; ">'.esc_textarea(stripslashes($txt)).'</textarea>';

So I can see the pictures, but when I try to open them, it gives this error. Any idea of how to solve this?

The link is http://gentsuniversitairkoor.be/media/fotos/ (it’s mostly in Dutch, but the plugin is still in English)

Thanks in advance!