Hi,
Do you have the latest daqmx drivers? You can download them from <a href="http://joule.ni.com/nidu/cds/fn/p/sn/n23:3478.41" target="_blank">here</a>.
Have you tried uninstalling and re-stalling MAX? There were some problems with MAX corruption with Labview 8.5, this <a href="http://digital.ni.com/public.nsf/allkb/AEE74EFEF7D6CA4E862573A90000A628?OpenDocument" target="_blank">KB</a> gives some instruction and more information on the problem. I'm not entirely sure if the problem was fixed with 8.5.1 or whether it is still in effect. It may be worth a try.
This <a href="http://forums.ni.com/ni/board/message?board.id=170&message.id=296077&requireLogin=False" target="_blank">thread</a> deals with corruptions of MAX, and may be a useful resource.
Regards,