>I am new to VFP OO coding & am having problems with one object modifying the properties of its parent.
>
>ex.
>oOne is created from a nonvisual class (OBJECT1), it creates an instance of OBJECT2 (oTWO), another class defined in the same prg file.
>
>Part of oTWO's job is to update a counter in oOne, so I include the following code in one of OJECT2's methods:
>
>THIS.PARENT.counter = THIS.PARENT.counter + 1
>
>When it executes I get the error message that THIS.PARENT is not an object & the debugger confirms this, parent = (none)
>
>I don't understand this at all. How could an oject created by another NOT have a parent value filled in?

'Parent' is reference to container object (if any exists) for the control, i.e. in your situation you may use it only if the second object is created as part of the first:
oMyobject1.Addobject("oMyobject2","MyClass2")
and later This.Parent issued from some method/event of oMyobject2 will refer to oMyobject1