Trovata la soluzione.
Quando avevo installato in locale Joomla 1.5.17 al primo accesso al sito (front end) avevo questa schermata:
Warning: strtotime() [function.strtotime]: It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'Europe/Paris' for '2.0/DST' instead in C:\xampplite\htdocs\edilizia\libraries\joomla\utilities\date.php on line 56
Warning: date() [function.date]: It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'Europe/Paris' for '2.0/DST' instead in C:\xampplite\htdocs\edilizia\libraries\joomla\utilities\date.php on line 198
Warning: date() [function.date]: It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'Europe/Paris' for '2.0/DST' instead in C:\xampplite\htdocs\edilizia\libraries\joomla\utilities\date.php on line 198
Benvenuto in Joomla!
Da una soluzione trovata sul web qualcuno aveva suggerito di togliere un underscore (_) sulla riga 52 del file date.php del path /libraries/joomla/utilities.
Effettivamente in locale con XAMPP l'errore non c'era più e non pensavo generasse questo problema con le date, negli oggetti di Joomla.
Fatto sta che ora tutto funziona, ma in locale mi rimane questo problema non ancora risolto.
Ciao