Null values or invalid date/time values were encountered while reading the input feature class.
Correct or reformat the values in the date/time field specified. If the problem is due to an invalid date/time format, use the Add Field tool to create a new date field; then use the Calculate Field tool to populate it. Often (but not always), Calculate Field will cast nondate fields into a valid date format. Alternatively, select all features with valid (non-null) values, and use the Copy Features tool to create a feature class that contains only valid values.