my $fh;
if( ! open($fh, '>>', 'XXX') ){ 
  # log error
} else { print $fh $email_message."\n-------------\n"; close $fh }

$mailprog = '/usr/sbin/sendmail';
open (MAIL, "|$mailprog -t >> XXX 2>&1");
print MAIL $email_message;
if( ! close (MAIL) ){
  # replace this with your error-logging facility
  print "Content-type: text/html\n\n";
  print "error, command failed with ".($?>>8)."<br>\n"
  print "message was:<br>\n${email_message}<br>\nEND message<br>\n";
} else {
  # EDIT: wrapped this in else!
  print "Location: application-submitted \n\n";
}