Sorry to resurrect an old thread, but I've been having this issue, on my test firewall, for at least 3 months, now. It's quite annoying, as it pops up fairly often, but not always. I've tried various clients, mostly Firefox 3.6.x, on Linux, Mac, and Windows. I've also tried Safari, on Mac, for client diversity.
The machine is a VIA Eden 1200mHz, using VIA Padlock hardware crypto. It's running x86 code, of course, currently on 2.0-BETA4, Tue Aug 10 02:57:56 EDT 2010 release. I've had this problem, on this machine, at least back to 2.0-BETA2. I don't, unfortunately have any sort of trace, though. I'd certainly be willing to collect info, though, if anyone has a suggestion on where to look.
I do have the following from /var/log/lighttp.error.log: (there are many repetitions of these)
cat lighttpd.error.log
2010-08-20 18:09:57: (connections.c.1698) SSL (error): 5 -1 22 Unknown error: 0
2010-08-31 19:53:28: (connections.c.1698) SSL (error): 5 -1 32 Broken pipe
These are not very specific, I know.
Thanks!