You gotta install also the following. As it says in the files
Part 2 - This part is required if you have not Split topic v 2 or greater
Part 3 - This part has to be installed if you haven't Categories hierarchy v 2.0.4 or greater
Since I don't have these installed, I'm about to do that now. But when I go to install #2, in preview I notice that I'm adding duplicate lines to the file viewforum.php. Same with #3. This tells me that I've done this B4, which is correct. When I preview #4 I get no file, only a critical error: Could not modify [%s], obviously because I don't have Split Topic or Categories installed.
I'm using digitaltwilight not subSilver, but the install accounted for that.
I just don't see any calendar...
I can add an event from within a post, but it only appears in the subject line after submitting.