Reappearing myname@atdmt.com tracking cookie?

Hello. The atdmt tracking cookie keeps reappearing on my system after deletion and after I have taken every security measure I can think of. I am running Firefox 3.6.10, and have Adblock Plus, BetterPrivacy (set to auto delete all LSO cookies every 2 min.), NoScript (w/only default sites white-listed) and Redirect Remover. My cookies setting in Firefox is set to accept no cookies whatsoever, save for a few sites i use that require them to even load; these being for my bank and yahoo - these however are only set for 'allow for this session' only. I have run a full scan w/both Malwarebytes and Norton Internet Security 2011 (the latter of which picks up the tracker). What am I missing here..?