Questo e`il form:

<form name="control_log" method="post" action="control_log.php">
<table width="155" cellpadding="0" cellspacing="0" border="0" bordercolor="#666666" style="border-collapse:collapse">
<tr>
<td colspan="2" height="1" bgcolor="#000000" valign="top"></td>
</tr>
<tr>
<td width="90" align="left">
<font face="Verdana" style="font-size:10px">
User ID
</font>
</td>
<td width="65" align="left">
<input type="text" name="userid" id="userid" size="10" maxlength="8">
</td>
</tr>
<td width="90" align="left">
<font face="Verdana" style="font-size:10px">
Password
</font>
</td>
<td width="65" align="left">
<input type="password" name="password_user" id="password_user" size="10" maxlength="8">
</td>
</tr>
<tr><td colspan="2" height="5"></td></tr>
<tr>
<td colspan="2" align="right">
<input name="invia" type="image" onclick="" value="invia" src="img/puls_invia.gif" hspace="2" vspace="0">
</td></tr></table>
</form>

------------------------------------------------------------------------------------
Questo e`il file control_log.php:
<?

$sql = "SELECT * FROM tabella where userid = '".$userid."' and password_user = '".$password_user."' and autorizza = 'Y'" ;
$result = mysql_db_query($database,$sql,$db) or die("Errore ".mysql_error());

$num_rows = mysql_num_rows($result) ;

if ( $num_rows != 0 ) {
// trovato
$row = mysql_fetch_array( $result );

session_register( "loggato" );
$loggato = true;

session_register( "id_ute" );
$id_ute = $row["id_ute"];

session_register( "userid" );
$userid = $row["userid"];

session_register( "nome" );
$nome = $row["nome"];

session_register( "password_user" );
$password_user = $row["password_user"];

session_register( "livello" );
$livello = $row["livello"];

session_register( "id_ute" );
$id_ute = $row["id_ute"];

session_register( "email" );
$email = $row["email"];

session_register( "accessi" );
$accessi = $row["accessi"];


header ("Location: office/split.php");

} else {
// non trovato
header ("Location: index.php?go=errore"); }

?>
----------------------------------------------------------------------------------

Questo e`il file che identifica l'utente e in base al livello mostra il suo pannello di controllo.
split.php

<?
session_start();
?>

<html>
<head>
</head>
<title>AREA RISERVATA </title>

<?

if (( $loggato == true ) and ( $livello == "webmaster"))


{

echo("<frameset cols=280,* frameborder=no border=0 framespacing=0>");
echo("<frame src=admin_office/menu.php name=menu scrolling=auto noresize>");
echo("<frameset rows=100,* frameborder=no border=0 framespacing=0>");
echo("<frame src=admin_office/testa.php name=testa scrolling=auto noresize>");
echo("<frame src=admin_office/corpo.php name=corpo scrolling=auto noresize>");
echo("</frameset>");
echo("<noframes></noframes></frameset>");


}

if (( $loggato == true ) and ( $livello == "amministratore"))


{

echo("<frameset cols=280,* frameborder=no border=0 framespacing=0>");
echo("<frame src=admin_office/menu.php name=menu scrolling=auto noresize>"); //correzione qui
echo("<frameset rows=100,* frameborder=no border=0 framespacing=0>");
echo("<frame src=admin_office/testa.php name=testa scrolling=auto noresize>");
echo("<frame src=admin_office/corpo.php name=corpo scrolling=auto noresize>");
echo("</frameset>");
echo("<noframes></noframes></frameset>");


}

if (( $loggato == true ) and ( $livello == "utente"))



{

echo("<frameset cols=280,* frameborder=no border=0 framespacing=0>");
echo("<frame src=user/menu.php name=menu scrolling=auto noresize>");
echo("<frame src=user/corpo.php name=corpo scrolling=auto noresize>");
echo("</frameset><noframes></noframes>");
echo("</frameset>");

}

if (( $loggato == true ) and ( $livello == "segretaria"))


{

echo("<frameset cols=280,* frameborder=no border=0 framespacing=0>");
echo("<frame src=admin_office/menu_segre.php name=menu_segra scrolling=auto noresize>");
echo("<frame src=admin_office/corpo_segre.php name=corpo_segre scrolling=auto noresize>");
echo("</frameset><noframes></noframes>");
echo("</frameset>");

}


else {

echo ("

");
echo ("<div align=center>");
echo ("





");
echo ("<font face=Arial style=font-size:18px color=#F90606>");
echo ("Per accedere al pannello devi loggarti");
echo ("</font>");
echo ("</div>");
}


?>

</html>


--------------------------------------------------------------------------
Le sessioni in control_log.php mi servono per le varie pagine.

Quello che non capisco e`perche`su un altro server funziona correttamente!

Grazie.
CIAO