In the Russian and Ukrainian interface language, in the Reminder tab, if you create a reminder with the occurrence set to once, the start date is in format xx/xx/xx. However, if you change the start date of reminder, the format of the date changes to xx-xx-xx and you may get a Wrong date error. Leaving the date untouched creates the reminder successfully. In order to change the date of the reminder, copy the “date format” section from the English language file to both the Russian and Ukrainian language files