What happens if you:

this doesn't
form.control.method()
  lo = newobject('anything')
  lo.oCreator = this
*  this.addproperty('oSomething',lo)
  this.AddProperty('oSomething')
  this.oSomething = lo
  lo = .NULL.
endproc
form.control.destroy()
  this.oSomething = .null.
endproc

anything.destroy()
  this.oCreator = .null.
endproc

Does that change anything? I've seen .AddProperty() act screwy if you initialize it with an object reference.