I'm guessing that's the description of your date field within CB > Field Management? If is the case you need to add the description to your CB language files then translate as needed. For example the language string would be as follows if the above is the exact string.
Code:
'The date of birth entered should use the format Year-Month-Day, i.e. 0000-00-00" or remove ?' => 'The date of birth entered should use the format Year-Month-Day, i.e. 0000-00-00" or remove ?',
You can remove fields from registration display by toggling their registration display off within CB > Field Management.
krileon
