This generic plan can help you in the creation of a solution:
- Define what constitutes an iinvalid value (e.g. bounds? invalid month-day-year-values? etc.)
- Translate these rules into a logical expression that checks whether a field is inside/outside these bounds
- Add this expression to an IF() function that displays an error message in a text box whenever the conditions are met.
Note that QV does not have an IsDate() test function. But you can easily use date#() for that. If date#() returns NULL, then either the values ( e.g. '99/99/9999') or the format (e.g. '1/ABC/2015') of the parameter or both are wrong.