I am suspicious that this problem may be related to the fact that Windows can not address more than 4GB of virtual memory per application at any one time. This sticks out in my mind because 4GB is a "magic number" that comes up a lot and dooms many applications.
Is it possible to verify whether the problem occurred with the older LabVIEW 6.1 version? Can you test using NI-DAQmx to see if the problem persists? How exactly are you reading the information from the file and presenting it to the DIO Write VI?
Message Edited by WM John Weeks on 12-01-2005 08:49 AM