Note to replicate this you have to use a specific version, as in
Gofer new     squeaksource: 'ZincHTTPComponents';     version: 'Zinc-HTTP-SvenVanCaekenberghe.191';     package: 'Zinc-Seaside';     load.
And then starting the Seaside adapter in one go.
On Mac OS X, I cannot reproduce this at all.
With Cog on some systems we had initially problems with Kom because the sockets were closed in a separate thread and we had to wait for that thread to terminate. I don't think Zn has any asynchronous behaviors. Or would it help to wait a second before the image is saved?
So I decided to revert back by pushing down the connection management functionality of ZnMultiThreadedServer to a new subclass called ZnManagingMultiThreadedServer. Now the code difference between working and failing code is even smaller. Note also that the server is just started, it is not yet receiving any connections!
Any help would be appreciated ;-)
Lukas, I think you could try to rebuild the failing Seaside jobs.
Thank you for looking into this. The jobs are rebuilding right now. Lukas -- Lukas Renggli www.lukas-renggli.ch