Error message appears when pasting elements from another copy of ArchiCAD (which was closed after copying the elements)
This behavior is a result of a speed optimization that was necessary to speed up copy/paste operations. When you copy library parts, they do not actually get copied onto the clipboard – instead they are saved into a temporary file, and only a link to the temporary file is placed on the clipboard. This is because the clipboard can not effectively handle large amounts of data.
When you close a copy of ArchiCAD, the temporary files related to it gets deleted. Therefore the clipboard content that refers to the temporary file also needs to be deleted. This is why your clipboard is empty when you try to paste the elements that you copied from the (since closed) ArchiCAD instance.
Keep the source ArchiCAD open until you paste your elements into the other instance of ArchiCAD.