[Plugin: Custom Post Template] Not working on 3.3.1

After installing plugin, posts won’t load in admin section at all. When it start loading sidebar, stop at this plugin box and show:

Fatal error: Call to undefined function wp_get_theme() in /home/emailme/newyorkation/wp-content/plugins/custom-post-template/custom-post-templates.php on line 164

http://ww.wp.xz.cn/extend/plugins/custom-post-template/