get_theme_data が 3.4で非推奨関数となり、wp_get_theme()になりました。
使い方は、以下のようにします。
<?php
$theme_data = wp_get_theme();
$theme_uri = $theme_data->ThemeURI;
$author_uri = $theme_data->Author_URI;
$version = $theme_data->Version;
$name = $theme_data->Name;
$description= $theme_data->Description;
$author = $theme_data->Author;
$template = $theme_data->Template;
$tags = $theme_data->Tags;
$tags = implode(',',$tags);
echo "version:{$version}<br />
name:{$name} <br />
description:{$description}<br />
author:{$author}<br />
template:{$template}<br />
{$tags}";
?>