If you don't have RESPONSEDATE as a question in your file, you will see a warning in your meta data transformation saying "No variable has been marked as response date". See image below:
To avoid the import error, you have to click on your right mouse button and a list appears what can be done. Click on the second option "Create Response Date variable"
After you selected that option, Dapresy will ask you if you would like to create a new one or if you would like to select an existing question to become your Response Date.
Create new: here have the option to have all respondents imported on a Date you set in the box, or you select Use import date. If that box is selected, all respondents will have the date of the day you are running the actual import.
Select existing: when selecting existing Dapresy will prompt you to select which question. It will show you only questions with the type Date or String/Open. In case you have a custom date format, you can match this with use custom Date format, see image below.
What else can you do during the meta data transformation?
All done? Continue!