Notice: Undefined index message

[stealthmode666]

New to .php so need script help.
I want to know how to stop this being displayed when I click submit.

Notice: Undefined index: homeowner in E:\domains\r\.. .\user\htdocs\. ..\form.php on line 166

I have an array which takes filled in fields and blank fields and sends them via email.
I DON'T need the user to fill in all the fields which is resulting in this notice on every field that is not filled in. I do need the fields to be sent tho' even if blank.
I have posted the scipt i have managed to piece together if this will help.
somehow I need the blank fields not to show me this notice.
I have started my .php script with this

<?php 
$to = $_REQUEST['sendto'] ; 
$from = $_REQUEST['Email'] ;
$name = $_REQUEST['Member_Name'] ; 
$headers = "From: $from"; 
$subject = "......"; 
 
$fields = array(); //I HAVE ABOUT 100 FIELDS
 
$body = ".........:\n\n"; foreach($fields as $a => $b){ $body .= sprintf("%20s: %s\n",$b,$_REQUEST[$a]); } 
 
$headers2 = "From: .......@....."; 
$subject2 = "Thank-you ......."; 
$autoreply = "Somebody.......";
 
if($from == '') {print "You have not ....";} 
else { 
if($name == '') {print "You have not .......";} 
else { 
$send = mail($to, $subject, $body, $headers); 
$send2 = mail($from, $subject2, $autoreply, $headers2); 
if($send) 
{header( "Location: http.....com/.../thankyou.html" );} 
else 
{print "We encountered an error sending your mail, please notify ...@...."; } 
 }
 }
?>

Sorry, but completey new to .php so I have no idea what i have to do to stop this notice from displaying, or how to script it into the above.
Any help will be appreciated.

[stealthmode666]

This is one of two scripts i'm using. Both are the same with the data fields in an array and the first script with about 10 fields on the page works no problem. If the user hits the submit it shows the field that needs to be filled in (I display text to tell them to go back and fill-in the required field) without all the notices appearing about undefined indexes.
I don't understand why one works perfectly and the other one shows all the unfilled fields?

[stealthmode666]

Solved the notice:Undefine d index in /....... 128
I used .js to insert a space in blank fields left by the user.