Same problem been happening to me a lot lately. It's a bug, IMO. along with all the other iC5 Bugs since it's Launch :ermm:That being said, you couldn't ultimately achieve what we do with any other Program, for the price.
My solution; If the Character has an Accessory eg; a hat, that's Attached & therefore a Character Sub-Node, Linking the Prop to the Accessory doesn't Display the Error Message, here. Then you can Link eg; the book to the Character's Hand Sub-Node.
You could try temporarily Applying a hat Accessory.
BTW - You can Link & Attach Objects by also Selecting the Parent in Scene Manager instead of Selecting the Parent in the Preview Screen. It's sometimes more convenient.
Anyone-else?