I have created a large 12x12 book with 118 pages in LR 4.4. Pressing "send to Blurb" doesn't work. Neither does the PDF option. No dialog box, no error message, nothing. I use a Mac. I did another "test" book from scratch this morning with just 9 pages, and, voila, the Blurb dialog box DID appear as it should. But when I went back to my larger book, again, it didn't work. What should I try next?