Here are some screenshots from SE V18 where this macro works just fine.
It generates a toolwindow with a context menu (see Capture1) that allows you to set some options and then 'generate' the ToDo list. This list shows up in the ToDo toolwindow in a by-file tree view (see Capture2) and, optionally, in the Message List (see Capture3). You can then double-click to navigate to the source file where the ToDo comment appears (see Capture4).
I normally keep it docked at the bottom of my main window along with Search Results, Preview, Build, Message List, and Output.
Very handy. Especially if you annotate your 'ToDo' comments to indicate what type of issue/change it refers to such as a temporary change due to testing a new feature.
The macro loads (apparently successfully) in V19 but the toolwindow never appears.
I haven't seen any posts from the original author of this macro in a couple of years.
Edit: BTW, I use another macro (CodeMarkup.e by chrisant, see this thread http://community.slickedit.com/index.php/topic,3633.msg17197.html#msg17197
) that highlights the 'ToDo' comments in the source code. Also very nice. This one works just fine in V19.