Unable to index : Caught exception while handling client http traffic

Hi,

I have a 2 node cluster, which was working fine, and since a few days
(after the leap second crash/restart it seems) I can't index anything.
I use a python script for bulk indexing (with pyes), and the execption
appears when I call "refresh".

the exception is : http://pastebin.com/vgawj1cH
the version is 0.19.4, on debian squeeze

Search is ok, and cluster health is green. Restarting both nodes, didn't
fix anything. any ideas?