aeiou-Namedays are undefined but the option to override them is set
Cause : In the Saints/Namedays Options of the current DiaryGridline you have checked the option to override the International Namedays, but have not supplied the reference to the set to use as override. The corresponding portion of the Saints and Namedays editor looks as shown below :
Consequences : Any reference to the corresponding aeiou-Namedays in the current DiaryGridLine will result in a blank.
•Change Saints/Namedays Options : Opens the Saints/Namedays Options property editor, so you can either select a Holidays Set or uncheck the option that triggered this message.