reject 450 NOQUEUE issue

[Jeff Lacki]

Im not nearly as versed in postfix as I would like to
be.  Ive tried to figure this log message out but Im not 
sure whats really going on:

Jul 13 23:36:08 mysvr postfix/smtpd[14133]: NOQUEUE: reject: RCPT from 
mms.nextel.com[170.206.225.68]: 450 4.7.1 <adcvibq01.messaging.nextel.com>: 
Helo command rejected: Host not found; from=<> to=<nob...@myserver.com> 
proto=ESMTP helo=<adcvibq01.messaging.nextel.com>

Im unsure if this is nextel.com replying back telling me
that my helo is invalid due to an invalid host and/or
my from=<> is a seperate issue.  Can someone point me in
the right direction?  If its my from=<> how do I set that?
What am I missing in the script below?

Ive got a perl script emailing an SMS text message
to <number>@messaging.nextel.com using the following 
perl function:

sub send_email_msg_sms
{
    my $helo = shift;
    my $to = shift;
    my $from = shift;
    my $subject = shift;
    my $msg = shift;

    open(MAIL,"|$SENDMAIL -t -F $from") || die "Opening sendmail pipe\n";
    print MAIL "HELO: $helo\n";
    print MAIL "To: $to\n";
    print MAIL "From: $from\n";
    print MAIL "Subject: $subject\n";
    print MAIL "\n";
    print MAIL $msg;
    print MAIL "\n";
    close(MAIL);
}

Thanks in advance,
Jeff