ed ha ragione....

dove vedi $sql impostata???
ma soprattutto l' inserimento lo fà lo stesso.. è la query dopo che non esiste...

fai così

Codice PHP:
$inserimento=mysql_query"insert into messaggi (id_user,username,password,user,gender,date_of_bir th,country,test_arousal_photo1,test_valence_photo1 ,test_arousal_photo2,test_valence_photo2,test_arou sal_photo3,test_valence_photo3,test_arousal_photo4 ,test_valence_photo4,test_arousal_photo5,test_vale nce_photo5,test_arousal_photo6,test_valence_photo6 ,test_arousal_photo7,test_valence_photo7,test_arou sal_photo8,test_valence_photo8,test_arousal_photo9 ,test_valence_photo9,test_arousal_photo10,test_val ence_photo10,date) values ('" $_POST['username']. "','" $_POST['password']. "','" $_SESSION['id_user']. "', '" $_SESSION['user']. "','" $_SESSION['gender'] . "','" $_SESSION['year'] . "-" $_SESSION['month'] . "-" $_SESSION['day'] . "','" $_SESSION['country'] . "','" $_SESSION['test_arousal_photo1'] . "','" $_SESSION['test_valence_photo1'] . "','" $_SESSION['test_arousal_photo2'] . "','" $_SESSION['test_valence_photo2'] . "','" $_SESSION['test_arousal_photo3'] . "','" $_SESSION['test_valence_photo3'] . "','" $_SESSION['test_arousal_photo4'] . "','" $_SESSION['test_valence_photo4'] . "','" $_SESSION['test_arousal_photo5'] . "','" $_SESSION['test_valence_photo5'] . "','" $_SESSION['test_arousal_photo6'] . "','" $_SESSION['test_valence_photo6'] . "','" $_SESSION['test_arousal_photo7'] . "','" $_SESSION['test_valence_photo7'] . "','" $_SESSION['test_arousal_photo8'] . "','" $_SESSION['test_valence_photo8'] . "','" $_SESSION['test_arousal_photo9'] . "','" $_SESSION['test_valence_photo9'] . "','" $_SESSION['test_arousal_photo10'] . "','" $_SESSION['test_valence_photo10'] . "', now())" ) or die (mysql_error());

echo 
"
Registrazione effettuata."
;
}
@
mysql_close($connection);