Not only did I figure this out, but I am currently using it to reset the dates of 150,000 folders (I copied a backup of my Laptop from one Archive drive to another) -- it's not the fastest process (it does on the order of 50 folders/second), but it's "hands-off".
As noted here and in the LabVIEW Discussion Forums, using the .NET calls in Windows 7 and attempting to do multiple files can lead to difficult-to-understand (and thus hard to program-around) errors. The technique that I used was to arrange things so that the only file I/O that was taking place was on the Target device whose Folders I was trying to modify. My routine requires two passes -- during the first pass, LabVIEW parses the Source Folder Tree and writes a text file containing the Folder Path and the Creation, Modification, and Accessed TimeStamps. The second pass reads (and closes!) this file, then applies all of the changes to the Target Folder Tree (assumed to mirror the Source Tree, which is the case as we used Windows to copy the Source Tree to the Target Tree).
