I'm having a bit difficulty deciding WHEN exactly it's useful enough to let the user know something went wrong. 
I am considering the following, please let me know if you want it different. 

Error handling only on: 1. Extracting an existing document. 2. Creating the temp directory for the extracted files to be put.

This because I will assume the files in the data/exploits/docx directory and the temporary directory I successfully created are always there and readable and creation of the compressed document is handled by msf.