The patch mentioned in the upstream bug report  is currently available in linux-backports-modules-jaunty. Please install, test, and let us know your results. Thanks.
 ogasawara@yoji:~/wireless-testing$ git log -p 49f606bca67f854ec87ae417cbc49fb3fc600ad0
Author: Zhu, Yi <email address hidden>
Date: Fri Dec 5 07:58:39 2008 -0800
iwlwifi: fix "MAC in deep sleep" error