It seems this was due to a change in lighttpd, see http://redmine.lighttpd.net/issues/2738

This change will be reverted in lighttpd 1.4.41. Meanwhile either use lighttpd 1.4.39 or you can use the workaround described here http://redmine.lighttpd.net/boards/2/topics/6758?r=6763#message-6763