Mail errors or attacks?

[David Baron <d_baron@012.net.il>]

I get a zillion of these, every single day, about every 5 minutes or so:

2010-05-24 15:05:38 SMTP call from localhost (dovidhalevi) [127.0.0.1] 
dropped: too many syntax or protocol errors (last command was "MAIL 
FROM:<jameswellington000.org@[71.121.223.194]> SIZE=8814")

I am running exim4 heavy on a Sid box.

Exim shows no stuck messages or such. How can I stop this?