It is possible that your computer thinks that the pdf file is a word document and tries to open it using word.
Solutions could be:
The file does not have a pdf extension when saved to PZ.
Save the file with a .pdf extension (for example fred.pdf) to your desktop and open.
Your pc is opening all .pdf files using word.
This may be due to adobe crashing.
Re-install adobe acrobat or download the latest updates or, save the pdf file to your desktop, right mouse click on the file and select “open with” and select Adobe.