You should open all documents from the browser-based Dashboard, as follows:
 

1. Go to the Dashboard directly within your browser or via Files/Docs >> Open Dashboard in browser in the Word menu. 

2. Locate Opportunity for your RFP project 

3. Click the Opportunity ID; this opens a window that shows all related documents 

4. Click on the hyperlink for the File Name 

 
See Opportunities view overview for more info