Sort of puzzle position from a completed Havannah game on Gamerz

Gamerz Havannah game 764, position after move 73

Green to move and win.

e6

f6 wins too (although it's a bit longer).

k10 and k11 as well.

Examining the URL http://www.gamerz.net/pbmserv/Havannah/Havannah.php?w=0&m=73, I wonder how the server would know to show game 764 if all I give it is that URL. And in fact the server is not showing me a Havannah game board at that URL. How is it that it's working for you folks?

It's not working. Goto Havannah games and pick 764.

or directly to game 764 and then click to move 73.

Now I get it. The site uses a cookie, not the URL, to keep track of which game it is, when you select a move within the game. I had cookies disabled.

74.E6 wins for Green, but that move would also have won earlier, as 68.E6. 71.C1 wins for Blue. What am I missing?

You miss nothing.