I too found that the "Task is done" vi did not fix the problem. However, the "Create Task" vi does fix the problem (see my earlier post for sample code). This vi copies the scan list from MAX. I also confirmed that the problem is fixed in Labview 7.1.1 which is available as a free download. However, in my application (I'm using a timed loop to acquire data every 10ms) 7.1.1 ran slower and was unsatisfactory, so I reverted back to v7.1.
I had code that had been working for several years, possibly making use of the property node _before_ anything else and then it stopped working and returned -200088.