Q: I am trying to finish up a project in iPhoto

First, do you mean you are using iPhoto or the new replacement for it named Photos?

OK. This is the Photos forum, not the iPhoto one. I asked the hosts to relocate your post to the correct forum.

that is a warning that someplace you have a text block with no text in it - you can go ahead and purchase - be sure to preview careful before ordering - iPhoto, Aperture: Previewing an order in iPhoto or Aperture - Apple Support

LN

Either do as Larry suggested or examine all the text boxes in the book for those that have no text but only the default text.  Put a space in those text boxes and you'll avoid the message.