I'm trying to add the paper from http://www.lfcs.inf.ed.ac.uk/reports/90/ECS-LFCS-90-123/ to my zotero. As soon as I add the pdf file (http://www.lfcs.inf.ed.ac.uk/reports/90/ECS-LFCS-90-123/ECS-LFCS-90-123.pdf) I cannot sync anymore. It gets stuck at around 5%, apparently while trying to upload the zip file to my dav server. It then aborts, giving me the red icon with exclamation mark. If I click that icon, it says:

"File upload failed. Please check your file sync settings or contact your WebDAV server administrator.

HTTP 0"

On the server's side, it logs

x.x.x.x - x [02/Oct/2014:09:01:50 +0200] "PUT /dav/x/zotero/PASTMRBH.zip HTTP/1.1" 408 221 "-" "Mozilla/5.0 (X11; Linux i686; rv:32.0) Gecko/20100101 Firefox/32.0" TLSv1.2 ECDHE-RSA-AES128-GCM-SHA256

It seems to be specific to this one pdf file.. removing that file makes things work, as does adding any other pdf file. Re-adding after removing and the issue is back.

I really can't see any problem on my dav server's side.