what’s wrong with my wordpress plugin

i download a pagebar plugin,and do it as it says,

Copy the file pagebar.php to your plugins directory and add the CSS code contained in pagebar.css to your style.css.
Then add the following code directly behind The Loop:
<?php wp_pagebar(array(‘before’=>’Pages: ‘))?>
but it still doesn’t work normally,what’s wrong? who can tell me where maybe get mistake?