admin.PHP3

<?
    INCLUDE("layout.inc.PHP3");
    INCLUDE("config.inc.PHP3");
    INCLUDE("./lang/$language.inc.PHP3");
    print_header("$admin_name");
    print_navbar();
    $string=implode($argv," ");
    $string2=explode("&",$string);    
    if($string=='')
{
echo"
     <p align=center>$program_name Version: $ver<br><br>Administration:</p>
     <form method=POST action=\"admin.PHP3?admin\">
     <table border=0 width=50%>
     <tr><td>$admin_username:</td><td><input type=text name=adminuser1></td></tr>
     <tr><td>$admin_password:</td><td><input type=password name=adminpass1></td></tr>
     <tr><td></td><td><input type=submit value=\"$send\"><input type=reset value=$reset></td></tr>
     </table>
     </form>
    ";
}

    else if($string=='admin')
{
if($adminuser1==$adminuser)
    {
    if($adminpass1==$adminpass)
{
echo"
     <p align=center>$admin_name:</p>
     <a href=../../\"admin.PHP3?send&$adminuser1&$adminpass1\">$send_mail</a><br><br>
     <a href=../../\"admin.PHP3?users&$adminuser1&$adminpass1\">$show_users</a><br><br>
     <a href=../../\"admin.PHP3?delall&$adminuser1&$adminpass1\">$del_table</a><br><br>
     <a href=../../\"tablecreator.PHP3\">$create_table</a>
    ";
}
else { echo"$noaccess"; }
    }
    else { echo"$noaccess"; }
}

    else if($string2[0]=='delall')
{
if($string2[1]==$adminuser)
    {
    if($string2[2]==$adminpass)
{
$query="DROP TABLE $maillist_table";
mysql_db_query($database_name,$query,$conn) or die("$cant_del_table");
echo"$table_deleted";
}
else { echo"$noaccess"; }
    }
    else { echo"$noaccess"; }
        }

    else if($string2[0]=='users')
{
if($string2[1]==$adminuser)
    {
    if($string2[2]==$adminpass)
{
echo"
      $headline_users<br><br>
      <table border=0 width=100% cellspacing=1><tr bgcolor=\"#000084\"><td width=25%>Name:</td><td width=25%>$prename:</td><td width=25%>E-Mail</td><td width=25%> </td></tr>
      ";
      $query="SELECT * from