Larry,
if you set an object's reference to .NULL., you will release the object (unless another object is holding a reference to it). If you have an object property which is an array, and which contains references to objects, then you have to do loop through the array, doing myArray(i) = .NULL. (as you describe). I found this out the hard way, with a form that refused to release. It's not enough just to let the array go out of scope.
Further to Mike's references, there's an excellent article in FoxTalk by Doug Hennig, which describes the problem you mention. Here's the link :
http://msdn.microsoft.com/library/periodic/period99/html/10ft/FT99J8.HTMBest wishes,
Neil