Go to Admin>Personnel>Staff and select the staff member's name that is causing the error from the drop down. Once the profile has loaded, please click the cog symbol next to their name to open their 'Personal Details' window, here you are able to amend their Newly Qualified Teacher status information.
Note: If the status is correct even though outside of the 2 year period, you'll need to add a validation note when submitting your census.