As I mentioned, earlier editions are available at Dropbox.
Copy & paste the current link:
http://dl.dropbox.com/u/62858730/Harpers%202012-10.pdf
and change the month, e.g. "10", to another 2-digit number like "09"
I always use the same format, YYYY-MM. The part "%20" is code for a space.
Don't worry about it.
Solutions work the same way:
http://dl.dropbox.com/u/62858730/Harpers%202012-09%20sol.pdf
unless the the official one wasn't available. Also, I usually post a scan of my solution after a week.
Then try (with the appropriate month):
http://dl.dropbox.com/u/62858730/Harpers%202012-09%20sol%20mine.pdf