Hjælp til modificering af php-fil

Jeg har fået en til at lave nedenstående fil til mig - idet jeg ikke selv kan lave php.
Men jeg har brug for en mindre ændring:
Det sted, hvor der bliver checket for at man vælger eet og kun eet array, skal man i stedet vælge MINDST eet - og så skal svarene selvfølgelig sendes med.
En der gider hjælpe?


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD><TITLE>Ny</TITLE>

<!-- Minus AutoDato -->
<META NAME="Generator" CONTENT="Stone's WebWriter 3.5">
<LINK REL="stylesheet" HREF="../css/sommer.css" TYPE="text/css">
</HEAD>

<BODY  BACKGROUND="../pics/orange-1.gif" leftmargin="5" topmargin="4">



<TABLE cellSpacing=0 cellPadding=0 width="100%" border=0>
  <TBODY>
  <TR>
    <TD width=13><A href="../index.htm"><IMG
      height=23 alt="" src="../pics/retur.gif" width=17 align=bottom
      border=0></A>&nbsp; <BR><IMG height=1 alt="" src="" width=19 align=bottom
      border=0> </TD>
    <TD vAlign=top noWrap align=left width="3%"><A
      href="../index.htm"><IMG height=19
      alt="" src="../pics/www.gif" width=143 align=bottom
      border=0></A>&nbsp;<BR></TD>
    <TD align=middle><IMG height=1 alt="" src="../pics/skub.gif" width=200
      align=bottom border=0> </TD></TR></TBODY></TABLE>


<CENTER>
<TABLE cellSpacing=0 cellPadding=0 width=700 border=0><TR><TD>
<IMG SRC="katbe-g.gif" BORDER="0" WIDTH="204" HEIGHT="29" ALIGN="bottom" ALT=""><BR>
<span class="txt">
<?php
if (count($_POST) > 0) {
    trimdata($_POST); //remove whitespace
    extract($_POST,EXTR_OVERWRITE); //overwrite existing vars with the posted vars
}

if ($submit) {
    //form validation
    $error = array();
    if (!$name) {
        $error[] = "Angiv venligst dit navn";
    }
    if (!$address) {
        $error[] = "Angiv venligst din adresse";
    }
    if (!$zipcode) {
        $error[] = "Angiv venligst dit postnr.";
    }
    if (!$city) {
        $error[] = "Angiv venligst bynavn";
    }
    if (!$checkbox0 && !$checkbox1) {
        $error[] = "Husk at vælge";
    }
    if (!$radio) {
        $error[] = "Husk at foretage valg";
    }

    //only send mail if there's no errors
    if (count($error) == 0) {
        //give user a message depending on checkbox choice
        if ($checkbox0 && !$checkbox1) {
            $text_msg = 'S';
        } elseif ($checkbox1 && !$checkbox0) {
            $text_msg = 'V';
        } elseif ($checkbox0 && $checkbox1) {
            $text_msg = 'S- og V';
        }
        $message = $name."\n";
        $message  .= $address."\n";
        $message .= $zipcode." ".$city."\n";
        $message .= "\n";
        $message .= $text_msg."\n";
        $message .= "Valg: ".$radio."\n";

    echo("Tak for din melding om ");
        echo $text_msg;
        mail('ntg@mail.dk', 'Tilbagemelding', $message);
        ;?>
        <p><a href="../index.html">Klik her for at fortsætte</a></p>
        <?php
    //if errors, give user some info...
    } else {
        echo join("<br>",$error);
    }
}

//show the form, if it is not sent, or errors ocurred
if (!$submit || count($error) > 0) {
    $radio_ary = array();
    $radio_ary[1] = 'J';
    $radio_ary[2] = 'P';
    $radio_ary[3] = 'I';
    $radio_ary[4] = 'B';
    $radio_ary[5] = 'F';
    $radio_ary[6] = 'I';
    $radio_ary[7] = 'C';
    $radio_ary[8] = 'S';
    $radio_ary[9] = 'F';
  $radio_ary[10] = 'M';
  $radio_ary[11] = 'A';
    ?>
    <form action="index.php" method="post">



<TABLE WIDTH="100%" BORDER="0" CELLSPACING="0" CELLPADDING="0"><TR><TD valign="top">



<TABLE WIDTH="200" BORDER="0" CELLSPACING="0" CELLPADDING="0">
<TR><TD><span class="txt">
Navn
</TD><TD>
<input type="text" name="name" value="<?= $name?>">
</TD></TR>

<TR><TD><span class="txt">
Gade
</TD><TD>
<input type="text" name="address" value="<?= $address?>">
</TD></TR>


<TR><TD><span class="txt">
Postnr&nbsp;&nbsp;
</TD><TD>
<input type="text" name="zipcode" value="<?= $zipcode;?>">
</TD></TR>


<TR><TD><span class="txt">
By
</TD><TD>
<input type="text" name="city" value="<?= $city?>">
</TD></TR>


</TABLE>

<BR><BR>
<span class="txt">
Vi vil bede dig...






</TD><TD width="150" align=center valign=top><span class="txt">
<IMG SRC="so.jpg" BORDER="0" WIDTH="150" HEIGHT="216" ALIGN="bottom" ALT=""><BR>
S<BR>
<input type="checkbox" name="checkbox0" value="checkbox0" <?php if ($checkbox0) print "checked";?>
</TD><TD width="40">
&nbsp;&nbsp;
</TD><TD width="150" align=center valign=top><span class="txt">
<IMG SRC="vi.jpg" BORDER="0" WIDTH="150" HEIGHT="216" ALIGN="bottom" ALT=""><BR>
V<BR>
<input type="checkbox" name="checkbox1" value="checkbox1" <?php if ($checkbox1) print "checked";?>
</TD></TR></TABLE>










<TABLE WIDTH="100%" BORDER="0" CELLSPACING="0"><TR>
<TD width=100%>





        <table border="0" cellpadding="0" cellspacing="0">
        <tr>
            <td>
                <table cellpadding="2" cellspacing="0" border="0">
                <?php
                foreach ($radio_ary as $key => $value) {
                    if ($radio == $value) $checked = "checked";
                    print "<tr><td><span class=\"txt\">
".$value."</td><td><input type=\"radio\" name=\"radio\" value=\"".$value."\" ".$checked."></td></tr>";
                    unset($checked);
                }
                ?>
                </table>
                </td>
            </tr>
            <tr>
                <td colspan="2" align="right"><BR><BR>
        <input type="submit" name="submit" value="Send "></td>
            </tr>
        </table>
    </form>
    <?php
}
?>




</TD></TR></TABLE>