I use NOD32 Antivirus and found that it was giving an alert for Microgaming and Playtech software about a year ago.
Recently it seems to be accepting Microgaming software without any problems, however it is still blocking Playtech software.
I posted an article on my site in February to update my readers: http://www.onlinecasinobonus.co.za/2009/02/16/nod32-anti-virus-software-false-positive-alerts/