URI for cdn theme files wrong

In my setup I enabling cdn for theme file was returning the wrong links like these:
http://domain.com/http://domain.com/path/to/theme/file.js

So I temporarily changed line 266 of lib/w3/plugin/cdn.php to get_theme_root instead of get_theme_root_uri, what can cause this issue?

http://wordpress.org/extend/plugins/w3-total-cache/