I'm sure it's ridiculous, but it's still driving me up the wall.

I've gone the semi-easy route and downloaded a premade script for an email form. The form will detect information that's required before submitting, and that part of it works because if I don't enter all of the fields with something, it will come back with an error message. However, when I get all of the information right and hit submit the damn thing will flash an error message that says it cannot modify the header information on line 90. The weirder thing is that I opened up my mailbox after one of these attempts and it'd sent my test email like 6 times.. one for every time I got frustrated and hit submit again and again. My question is how do I fix this? I'm still getting a grasp on this PHP thing and I'm about to rip some hair out over this.. here is my code.

HTML code:
HTML Code:
<font style="font-size: 7.5pt;">
<FORM ACTION="emailform.php" METHOD="POST">
<B>Your Name:</B> <br /><INPUT NAME="fromname" TYPE="text" SIZE="25" style="background-color: #FDF3F7; font-size: 7.5pt; font-family: verdana; color:#828282; border: 1px solid #F1DAE4; "><BR>
<B>Your Email:</B> <br /><INPUT NAME="fromemail" TYPE="text" SIZE="25" style="background-color: #FDF3F7; font-size: 7.5pt; font-family: verdana; color:#828282; border: 1px solid #F1DAE4; "><P>
<INPUT TYPE="hidden" NAME="sendpage" VALUE="sent.php">
<INPUT TYPE="hidden" NAME="subject" VALUE="From The Website">
<INPUT TYPE="hidden" NAME="toemail" VALUE="slimjadey@swbell.net">
<INPUT TYPE="hidden" NAME="require" VALUE="fromname,fromemail,message">
<B>Message</B><BR>
<TEXTAREA NAME="message" ROWS="3" COLS="30" style="background-color: #FDF3F7; font-size: 7.5pt; font-family: verdana; color:#828282; border: 1px solid #F1DAE4; "></TEXTAREA></P>
<P><INPUT NAME="submitform" TYPE="submit" VALUE="Submit" style="background-color: #F5F5F5; font-size: 7.5pt; font-family: verdana; font-weight: bold; color:#828282; border: 1px solid #F1DAE4; "></FORM></P>
</font>
PHP code:
PHP Code:
<HTML>
<HEAD>
  <TITLE>Email Form v1.1 - Powered by: (http://www.phpscriptcenter.com/emailform.php)</TITLE>
</HEAD>
<BODY BGCOLOR="#ffffff">
<!--

Powered by: Email Form Version 1.1 (http://www.phpscriptcenter.com/emailform.php)

-->
<?php

///////////////////////////////////////////////
//                                           //
// Email Form v 1.1                          //
// ----------------------------------------- //
// by Graeme (webmaster@phpscriptcenter.com) //
// http://www.phpscriptcenter.com            //
//                                           //////////////////////////////
// PHP Script CENTER offers no warranties on this script.                //
// The owner/licensee of the script is solely responsible for any        //
// problems caused by installation of the script or use of the script    //
//                                                                       //
// All copyright notices regarding Email Form, must remain               //
// intact on the scripts and in the HTML for the scripts.                //
//                                                                       //
// (c) Copyright 2001 PHP Script CENTER                                  //
//                                                                       //
// For more info on Email Form,                                          //
// see http://www.phpscriptcenter.com/emailform.php                      //
//                                                                       //
///////////////////////////////////////////////////////////////////////////

// your name
$yourname "Your Name";

// your email
$youremail "Your Email";

// Default Send Page
$yourdefaultsend "http://www.phpscriptcenter.com/sent.php";

////////////////////////////////////////////////////////////////////////////
//                      DO NOT EDIT BELOW THIS LINE                       //
////////////////////////////////////////////////////////////////////////////



if($submitform) {

$dcheck explode(",",$require);
while(list(
$check) = each($dcheck)) {
if(!$
$dcheck[$check]) {
$error .= "Missing $dcheck[$check]<BR>";
}
}

if(
$error) {
?>
<P><CENTER><TABLE BORDER="0" CELLSPACING="0" CELLPADDING="0">
  <TR>
    <TD WIDTH="100%" BGCOLOR="#004080">
    <TABLE WIDTH="394" BORDER="0" CELLSPACING="1" CELLPADDING="2">
      <TR>
        <TD WIDTH="26%" BGCOLOR="#004080">
        <P><B><FONT COLOR="#ffffff" SIZE="-1" FACE="Verdana">Error</FONT></B></TD>
      </TR>
      <TR>
        <TD WIDTH="26%" BGCOLOR="#ffffff">
        <FONT COLOR="#000000" SIZE="-1" FACE="Verdana"><?php echo $error?></FONT></TD> 
      </TR>
    </TABLE></TD>
  </TR>
</TABLE></CENTER>
<P><CENTER>&nbsp;</CENTER></P>
<P><CENTER><FONT SIZE="-2" FACE="Verdana"><B>Powered by:</B> <A HREF="http://www.phpscriptcenter.com/emailform.php">Email Form</A> Version 1.1</FONT></CENTER></P>
</BODY></HTML>
<?php
exit();
}

if (
$fromname) {
$yeshow "\nFrom, $fromname\n";
}

mail($toemail,"$subject","

$message

$yeshow

"
,"From: $fromname <$fromemail>");

header("Location: $sendpage");
exit();

} else {

?>
<FORM ACTION="emailform.php" METHOD="POST">
<P><CENTER><TABLE BORDER="0" CELLSPACING="0" CELLPADDING="0">
  <TR>
    <TD WIDTH="100%" BGCOLOR="#004080">
    <TABLE WIDTH="394" BORDER="0" CELLSPACING="1" CELLPADDING="2">
      <TR>
        <TD COLSPAN="2" BGCOLOR="#004080">
        <B><FONT COLOR="#ffffff" SIZE="-1" FACE="Verdana">Contact Form</FONT></B></TD>

      </TR>
            <TR>
        <TD WIDTH="48%" BGCOLOR="#ffffff">
        <B><FONT COLOR="#000000" SIZE="-1" FACE="Verdana">Your Name:</FONT></B></TD>
        <TD WIDTH="52%" BGCOLOR="#ffffff">
        <INPUT NAME="fromname" TYPE="text" SIZE="25">
</TD>
      </TR>
      <TR>
        <TD WIDTH="48%" BGCOLOR="#ffffff">
        <B><FONT COLOR="#000000" SIZE="-1" FACE="Verdana">Your Email:</FONT></B></TD>
        <TD WIDTH="52%" BGCOLOR="#ffffff">
        <INPUT NAME="fromemail" TYPE="text" SIZE="25">
</TD>
      </TR>
      <TR>
        <TD COLSPAN="2" BGCOLOR="#ffffff">
        <B><FONT COLOR="#000000" SIZE="-1" FACE="Verdana">Message:<BR><INPUT
        TYPE="hidden" NAME="subject" VALUE="Contact Form">
        <INPUT TYPE="hidden" NAME="toemail" VALUE="<?php echo $youremail?>">
        <INPUT TYPE="hidden" NAME="toname" VALUE="<?php echo $yourname?>">
        <INPUT TYPE="hidden" NAME="require" VALUE="fromname,fromemail,message">
        <INPUT TYPE="hidden" NAME="sendpage" VALUE="<?php echo $yourdefaultsend?>">
        <TEXTAREA NAME="message" ROWS="5" COLS="45"></TEXTAREA></FONT></B></TD>
      </TR>
    </TABLE></TD>
  </TR>
</TABLE></CENTER></P>

<P><CENTER><INPUT NAME="submitform" TYPE="submit" VALUE="Submit"></CENTER></FORM></P>
<P><CENTER>&nbsp;</CENTER></P>
<P><CENTER><FONT SIZE="-2" FACE="Verdana"><B>Powered by:</B> <A HREF="http://www.phpscriptcenter.com/emailform.php">Email Form</A> Version 1.1</FONT></CENTER></P>
</BODY></HTML>
<?php
exit();

}

?>
Any help would be greatly appreciated..