[racket] strange issue with tcp-connect on Windows...

Matthew can address the Racket internals questions, but one thing I'd 
check, if you haven't already...

At the moment of the error, have all the free TCP ports on one of the 
involved nodes been exhausted?  You can probably check this on the 
individual hosts close enough to the moment of the error, even if you 
can't check at the exact moment.

You can also reconstruct likely TCP stack states of each host after the 
fact, if you capture all the TCP traffic of each node on the wire, and 
you can also see whether protocol that should be happening (e.g., 
shutdown handshake) isn't happening on the wire in a timely enough 
manner.  (To help sniff traffic between N hosts on a LAN without the 
additional complications of hacking an OpenWRT device, I got an old 
*unswitched* Ethernet hub off eBay.  You might already have better 
network test equipment, but I'm mentioning this for any random person 
who reads this later.)

Neil V.