This is usually a problem with your templates in the Document Template Manager. Please use that link to learn more about how to use the Document Template Manager.
Open the Template manager and look at the templates under the 'Reviews' section. There should be several loaded in by default. If you open these templates and notice merge fields that look like this:
This is an indication that your templates need to be updated. Make note of which merge fields are shown this way, then add the correct merge fields to the template from the 'Open Merge Fields' menu (you will need to close the template to do this). Then reopen the template in question and replace the faulty ?MERGE_FIELD? with the correct <<MERGE_FIELD>>.
It is recommended to verify each template to make sure that the merge fields are included correctly.