A family of Microsoft relational database management systems designed for ease of use.
You need some separator characters between the parts of the date before the query can process it into a real date value. See if it works when you enter 9 Sept 12 or use the style in the prompt 9/sept/12 or any number of equivalent date styles.
Alternatively, you could take the next step and use a form with text boxes to enter the start and end dates. Then the query criteria would look like:
Between Forms!theform.txtstart And Forms!theform.txtend
Doing it this way gives you another option where you can use code to convert an undelimited date to a real date for the query to use.