Won't matter if there's an oops in the date or time anymore (they're user inputted, I can't avoid user error) with GJ 2.5 stable as you can now freely edit events in the past now. I recommend using the drop-down selects though to select dates and times.

... mmm, not in mine! when i try to edit a 1970's event GJ tell me i can't edit becouse the event it's out of date! for select the date... i haven't the calendar, where i have to edit this?

The change was implemented into GJ 2.5 stable, scheduled for release soon.

anywhere, it's possible to set the date in the "italian mode" (declare first the day & after the mounth)? & other, this plugin take some info/set from other component, like eventlist?

The date is drop-downs. The order of the drop-downs changes based off your configuration of the date format in CB > Configuration > General. As for the time format, no, it's AM/PM or 24HR. I will not add any further formatting, sorry.

If the calendar is not showing then you've a jQuery problem as jojo has mentioned. Alternatively you maybe using the old calendar as configured in CB > Configuration > General if there are not drop-downs and just an input with a calendar button.