Can't find string terminator "__STOP_OF_MAIL__" anywhere before EOF at birdcast.cgi line 115.

sub process_mail
{
for ($i=1;$i<$MAXNUM+1;$i++)
{
$recipname="recipname_$i";
$recipemail="recipemail_$i";
if ($fields{$recipemail} eq "")
{
next;
}
if (&valid_address == 0)
{
next;
}

#BNB SAYS! You can modify the Subject line below.

$subject = "A link from your friend $fields{'send_name'}";

#BNB SAYS! Modify the lines below between the lines marked
# with __STOP_OF_MAIL__ to customize your e-mail message
# DO NOT remove the lines that contain __STOP_OF_MAIL__!
# If you enter any hardcoded e-mail addresses, BE SURE TO
# put the backslash before the at sign, ie, me\@here.net

$msgtxt = <<__STOP_OF_MAIL__;
Hi $fields{$recipname},

$fields{'send_name'} stopped by $SITE_NAME
and suggested that you visit the following URL:

Site Name: $rec{'Title'}
Site Location: $rec{'URL'}
Site Description: $rec{'Description'}

__STOP_OF_MAIL__

if ($fields{'message'} ne "")
{
$msgtxt .= "Here is their message....\n";
$msgtxt .= "$fields{'message'}\n\n";
}
$msgtxt .= "$SITE_NAME\n";
$msgtxt .= "$ENDLINE\n";
$msgtxt .= "$SITE_URL\n\n";
$mailresult=&sendmail($fields{send_email}, $fields{send_email},
$fields{$recipemail}, $SMTP_SERVER, $subject, $msgtxt);

if ($mailresult ne "1")
{print "Content-type: text/html\n\n";
print "MAIL NOT SENT. SMTP ERROR: $mailresult\n";
exit
}

}
}