I deleted the symlink I placed, then updated this package to version 1:0.8~svn-rev31-3, but the same error occurs and Qt is not used.
$ gnome-about (gnome-about:23694): Gtk-WARNING **: Unable to locate theme engine in module_path: "qtengine", (gnome-about:23694): Gtk-WARNING **: Unable to locate theme engine in module_path: "qtengine", -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]