$result = mysql_query("SELECT username FROM ".$DBprefix."signup WHERE username='$nickname'") or die(mysql_error()); 
 
if (mysql_fetch_field($result) != $adres) { 
echo"Unknown user";    
} else { 
$datetime = date("Y-m-d G:i:s ");
    $query = mysql_query("INSERT INTO ".$DBprefix."inbox (messageID,adres,sender,DateRecieved,title,message,isRead) values ('','$adres','$nickname','$datetime','$subject','$content','')");
    echo"Your message has been sent to $adres";
} 
} 
$result = mysql_query($query);