尝试更新多行，数据加载，只是不更新

Thanks for looking to help, i'm having trouble getting this script to update the records in the database, it draws them out ok just doesn't update the records. I've been working on it for the past few hour and just can't get the update query to actually update the database

    $sql="SELECT * FROM $tbl_name";
    $result=mysql_query($sql);

    // Count table rows 
    $count=mysql_num_rows($result);
    ?>
    <table width="500" border="0" cellspacing="1" cellpadding="0">
    <form name="form1" method="post" action="">
    <tr> 
    <td>
    <table width="500" border="0" cellspacing="1" cellpadding="0">


    <tr>
    <td align="center"><strong>Id</strong></td>
    <td align="center"><strong>Name</strong></td>
    <td align="center"><strong>Lastname</strong></td>
    <td align="center"><strong>Email</strong></td>
    </tr>
    <?php
    while($rows=mysql_fetch_array($result)){
    ?>
    <tr>
    <td align="center"><? $id[]=$rows['id']; ?><? echo $rows['id']; ?></td>
    <td align="center"><input name="name[]" type="text" id="name" value="<? echo $rows['name']; ?>"></td>
    <td align="center"><input name="lastname[]" type="text" id="lastname" value="<? echo $rows['lastname']; ?>"></td>
    <td align="center"><input name="email[]" type="text" id="email" value="<? echo $rows['email']; ?>"></td>
    </tr>
    <?php
    }
    ?>
    <tr>
    <td colspan="4" align="center"><input type="submit" name="Submit" value="Submit"></td>
    </tr>
    </table>
    </td>
    </tr>
    </form>
    </table>
    <?php
    // Check if button name "Submit" is active, do this 
    if($Submit){
    for($i=0;$i<$count;$i++){
    $sql1="UPDATE $tbl_name SET name='$name[$i]', lastname='$lastname[$i]', email='$email[$i]' WHERE id='$id[$i]'";
    $result1=mysql_query($sql1);
    print($result1);
    }
    }

    if($result1){
    header("location:update_multiple.php");
    }
    mysql_close();

@ michael gorman:get the update query from the admin interface in mysql it self,i encountered this problem in the past,there will be a little difference between the query you write and that is exist in the admin interface of mysql,get it(copy and paste)then change the parameters as you want.

basic error checking:
echo $sql1, is it what you expect
check the query actully worked
return the error from mysql with mysql_error() if it did not