When starting a new CIS worker, you must create and send a CISVER before validating timesheets.
If you do not send this then when you are trying to validate the timesheets you will receive an error message and will not be able to continue until such time as you have sent this from your PAYE Online area.
if you enter all of the verification details in to Access Profile before exporting the worker to Pay & Bill, you will not need to create a CISVER as it will have been verified in Access Profile.