Pkg xen devel - Jan 2014 - Xen 4.1, wheezy, pciback -> NETDEV WATCHDOG: eth0 (via-rhine): tx queue 0 timed out

Apologies if this is posted on the wrong list, but when I try to get 
pci passthrough to work on a Wheezy Xen box I get

    NETDEV WATCHDOG: eth0 (via-rhine): transmit queue 0 timed out
    
and then not much else works at all.  The same hardware works just 
fine with Xen and Squeeze.  It seemed to me that the problem I am 
seeing is very similar to 

    https://bugzilla.kernel.org/show_bug.cgi?id=15833
    
but I have had no response to my posting on this bug report.  (I have 
not reproduced the details in this mail so as to try and keep it brief).

If anyone can point me the right direction I would be very grateful.

Apologies again if I am posting on the wrong list,

Jo.