What you have is a corrupted database entry for that book.
Are you able to create a new book, add photos and work with it?
Had a similar problem and could work on another book but not the corrupted book. Couldn't even delete the corrupted book as iPhoto would hang before I could delete it.
I completed the new book and then rebuild the library with iPhoto Library Manager (see below) to get rid of the corrupted book (and all other books, cards, slideshows, etc.).
May I suggest an alternate workflow for books:
1 - create a new library for each book
2 - use the paid version of iPhoto Library Manager to move the photos for the book from your working library to the book library.
3 - when the book is completed and ordered you can copy the library to a CD or DVD to save it in case you'll want to order another copy at a later date.
Using iPhoto Library Manager to Rebuild Your iPhoto Library
Download iPhoto Library Manager and launch.
Click on the Add Library button,
and select the library you want to add from those in the selection window.
Now that the library is listed in the left hand pane of iPLM, click on your library and go to the Library ➙ Rebuild Library menu option
In the next window name the new library and select the location you want it to be placed.
Click on the Create button.
Note 1: This creates a new library based on the LIbraryData.xml file in the library and will recover Events, Albums, keywords, titles and comments. However, books, calendars, cards and slideshows will be lost.
Note 2: Your current library will be left untouched for further attempts at a fix if so desired.
OT