I've gotten the "failed to create message" on a few occasions. I usually try freeing up RAM, and writing the PDF to a brand new location (such as my desktop).
If that fails, 9 times out of 10 it's a font issue. Disable all fonts in the document, see if the PDF writes. Then add each font back in one at a time, trying the export each time to see which font makes it fail.
One time I had a job with a corrupt empty text box. I had to load the font it referenced before I could even delete it.
If it's not a font, it's probably a support file. Set all support files to non-printing, then back to printing one at a time, exporting each time to see which one triggers the failure
You should not have to stitch together pieces to make a PDF. InDesign will make your PDF.