OK, my understanding
The timeout error happens because the WebIDE gets annoyed that Espruino is busy, and sends a ctrl-c, which breaks Espurino out of comms and causes the error. Ideally Gordon should give us a webide option to delay the ctrl-c
The Wiznet subsystem (i.e. wiznet+espruino) has at least two known problems: the -7 error and the out of sockets error. The -7 error means "socket has wrong state" - internally we're trying to do something on a socket that is closed. I don't yet know why.
Gordon has said that if you delay between GETS you don't run out of sockets, but I've not seen this - if I do repeated POSTS with a 2-minute delay I still run out after 8 POSTS.
When I have time, I'm still digging into this - I've got Espruino building and I've added logging to the code, but I've not quite got to the point where it's telling me anything useful...