I tried exporting the PDF . It it worked at some points along the process of making the document, but once I completed the document, it is no longer able to create a PDF. I did a whole lot of searching online and some people say it might have to do with scaled-down images. But as my images are all the same size and I was at various points able to export PDFs of this, I don't think that is the issue.. I am not getting any error warnings either.
See Adobe Community: File Crashing on Output - printing/PDF/other for troubleshooting tips.
Was this file converted from an earlier version by opening the .indd file in a newer version? We see this kind of problem with converted legacy files from time to time, and they happen without warning.