Searching for info about IncompleteRead errors with Python, the most common cause seems to be errors in HTTP/1.1 chunking, usually on the server side.
According to the log file, you're hitting AO3 stories. That's a very popular site, and I'm not hearing about that error from other people nor seeing it myself. So I'm going to assume that it's not a server issue. Which suggests it's something in between, like a proxy, firewall or masquerading router.
I found at least one reference about
virus detector/firewall was causing this problem. "Online Shield" part of AVG. Are your AV, firewall, etc all up to date? If you run a local firewall or proxy, can you try disabling it?
Quote:
Originally Posted by sam007
Hi,
I was using FFF on linux ok, but I can't seem to be able to make it work on Win7 (64bit). Sometimes it download the story, but not very often (and it definitely doesn't depend on the story - as the same url is like 1 out of 10 times downloaded.)
I have Calibre 64-bit , but I tried it with 32-bit too and then tried it with deleted options/config in AppData.
Here is the log of Calibre 64 with clean state.
I can upload the other log files too if needded.
 for your  |