This is a theme for D4X (Downloader 4 X) which is a very good download manager. You will have to use at least D4X v2.5.0 final for this theme, since that's when PNG transparency was introduced.
This theme is meant for a better integration with the Ubuntu desktop. It is quite different from the other Gnomeria-D4X theme in that it is more "serious" and more "gnomish".
If you want Gnome icons in the log panel too, you have to recompile D4X (D4X limitation). Read README.log_icons in the tarball for details.