I have obtained all three pieces of the invisibility cloak ie the ribbon,collar & cloak but the program does not recognize that fact and will not allow me to assemble and use. Any suggestion and/or advice?

you need the ribbon, collar (yellow dust pieces) and the coat (pink dust piece). When you got at least 1 of all those three you should be able to assemble.

If you are lacking one or two you can build them from your coloured mojo (when you have enough pieces).

Keep in mind you need CC protection for your parlours to make this item usefull.