This is because of my lack of understanding of the Autoit objects. This does not return an array of objects but a collection which must be accessed through a different way.
Hope this helps someone else.
$collection = _IEFrameGetCollection($ObjIE)
$max = @extended
ConsoleWrite("Array Length: " & $max & @CR)
For $item = 0 to $max - 1
$obj = IEFrameGetCollection($ObjIE, $item)
ConsoleWrite("Value" & $item.src)
Next