致命错误：无法实例化不存在的类：directoryiterator

Need some help with this error. Fresh wordpress 2.9 install...

Fatal error: Cannot instantiate non-existent class: directoryiterator in /home1/test/public_html/test2/wp-content/themes/mytheme/functions.php on line 471

function get_dirs($path = '.') {
$dirs = array();
foreach (new DirectoryIterator($path) as $file) {   //THIS IS LINE 471
    if ($file->isDir() && !$file->isDot()) {
        $dirs[] = $file->getFilename();
    }
}

return $dirs;

}

The DirectoryIterator class is part of the Standard PHP Library (SPL), which is installed by default in PHP 5. Maybe you are using PHP 4?

EDIT

To get information on your PHP installation, use phpinfo(). Create a .php file with this single line and open it in your browser:

<?php phpinfo() ?>