This run-time message occurs if:
•Q++ finds a :z or :Z string immediately after the minicalendar marker part of a minicalendar token,
•and the second character after the z or Z is one of the following: 2, 3, 4, 5, or 6,
•and the character immediately after the z or Z is not one of the allowed operator characters: n, N, <, >, ~ or =.
Based on the first 2 points above, Q++ assumes that this is either a Number of Days or a Number of Weeks Minicalendar Modifier. However, point 3, above, means that the comparison operator is incorrect.