So I’m here in Sorrento, Italy at our dev conference and struggling mightily
to get a good clone of the 5.1 repository on my box.  You see I’m using
BitKeeper with plink (ala Putty) as the SSH tunnel.  The wireless
connection on my Inspiron 6000  keeps going down and coming back up and
this is something that plink simply can’t stand. 

So I installed OpenSSH for Windows (yes the abandoned project that is sort of
being maintained).  Worked first time.  Apparently the stock ssh
client that comes with cygwin (and therefore with OpenSSH for Windows) is much
more tolerant of unstable network connections.