Ayudenme por fa!!

<?
include("../config.php");
if (isset($_REQUEST["submit"])){
extract($_REQUEST);
$sql="SELECT * FROM mon_usuario WHERE codigo_usuario = $rut";
$result=odbc_exec($cid,$sql)or die(exit("Error en odbc_exec()<br>$sql"));
if (!$result){
print "<p class=info><b>ERROR!! al Grabar</b></p>";
}
else{
$a = odbc_result($result,1);
$b = odbc_result($result,2);
$c = odbc_result($result,3);
$d = odbc_result($result,4);
$e = odbc_result($result,5);
print "<FORM ACTION='' METHOD='POST' AutoComplete='off' name='guardar'>";
print "<TD><INPUT VALUE=$a TYPE=HIDDEN NAME='aa' ID='aa'></TD>";
print "<TABLE ALIGN=center>";
print "<TR>";
print "<TD><FONT CLASS='info'><b>Rut</b></FONT></TD>";
print "<TD><INPUT CLASS='campo' VALUE=$a TYPE=text NAME='ru' ID='ru' SIZE=15 MAXLENGTH=10></TD>";
print "</TR>";
print "<TR>";
print "<TD><FONT CLASS='info'><b>Nombre</b></FONT></TD>";
print "<TD><INPUT CLASS='campo' VALUE=$b TYPE=text NAME='nom' ID='nom' SIZE=25 MAXLENGTH=25></TD>";
print "</TR>";
print "<TR>";
print "<TD><FONT CLASS='info'><b>Apellido</b></FONT></TD>";
print "<TD><INPUT CLASS='campo' VALUE=$c TYPE=text NAME='ape' ID='ape' SIZE=25 MAXLENGTH=25></TD>";
print "</TR>";
print "<TR>";
print "<TD><FONT CLASS='info'><b>Usuario</b></FONT></TD>";
print "<TD><INPUT CLASS='campo' VALUE=$d TYPE=text NAME='usu' ID='usu' SIZE=15 MAXLENGTH=10></TD>";
print "</TR>";
print "<TR>";
print "<TD><FONT CLASS='info'><b>Contraseña</b></FONT></TD>";
print "<TD><INPUT CLASS='campo' VALUE=$e TYPE=password NAME='pas' ID='pas' SIZE=15 MAXLENGTH=10></TD>";
print "</TR>";
print "</TABLE>";
print "<TABLE ALIGN='center' BORDER='0' CELLPADDING='1' CELLSPACING='4'>";
print "<TR>";
print "<TD><br><INPUT CLASS='boton' TYPE='submit' ID='sub' NAME='sub' VALUE=Grabar></TD>";
print "</TR>";
print "</TABLE>";
print "</FORM>";
}
}
if (isset($_REQUEST["sub"])){
extract($_REQUEST);
$sql1 = "UPDATE mon_usuario SET codigo_usuario=$ru, nombre=$nom, apellido=$ape, usuario=$usu, password=$pas WHERE codigo_usuario=$aa";
$result1=odbc_exec($cid,$sql1)or die(exit("Error en odbc_exec()<br>$sql1"));
if (!$result1){
print "<p class=info><b>ERROR!! al Grabar</b></p>";
}
else{
print "<p class=info><b>Informacion Grabada con EXITO!!</b></p>";
}
}
?>
<HTML>
<HEAD>
<LINK REL=stylesheet HREF="../principal.css" TYPE="text/css">
</HEAD>
<BODY>
<br><br><br>
<center><img src="../image/logomoni.gif"></center>
<br><br>
<center><p class=info><b>REGISTRO...</b></p></center>
<FORM ACTION="" METHOD="POST" AutoComplete="off" name="buscar">
<TABLE ALIGN="center">
<TR>
<TD><FONT CLASS="info"><b>Rut</b></FONT></TD>
<TD><INPUT CLASS="campo" TYPE="text" NAME="rut" ID="rut" SIZE="15" MAXLENGTH="10"></TD>
</TR>
</TABLE>
<TABLE ALIGN="center" BORDER="0" CELLPADDING="1" CELLSPACING="4">
<TR>
<TD><br><INPUT CLASS="boton" TYPE="submit" ID="submit" NAME="submit" VALUE="Buscar"></TD>
</TR>
</TABLE>
</FORM>
</HTML>