The problems were a kind of "mismatch" with the dates, a confusion between the european styles and the anglo-saxon styles.
Days were interpreted as month and vice versa. Aggravated to the point of putting some date in the futur (2018, ... 2024).
It took some hours to correct the errors, everything is fine now.
That lead me to my next question : How long will it take you copy some three hundred hours from my paper logbook to the computerized one ?