Hi Jang,
Thank you very much for your great script and for your willingness to help newbies like me! You are a real professional! 
Your script is impressive! It managed to replace 99.9% of the content in a file, and the file only lost 1KB from its size. I wonder what could make it pass over some sentences in several paragraphs, and a table. This is more than interesting and worth exploring. Another caveat: there is no "Undo" (not criticism at all -- just food for thought/regular user input 
).
I guess if one wants to run this script on a book, the script must be somehow called from the sample iterator.jsx provided by Adobe or something similar. Am I right?
Thank you very much again for sharing the script with us!!!