Send mail message makes stuck the buttons and forms

I did a send e mail control application and when I run it within onValidateSuccess code it sends the mail but then … the application goes stucked. No way to go back or exit from it

This is the code for showing messages after sending but probably something is wrong.

sc_mail_send($mail_smtp_server,
$mail_smtp_user,
$mail_smtp_pass,
$mail_from,
$mail_to,
$mail_subject,
$mail_message,
$mail_format,
$mail_copies,
$mail_tp_copies,
$mail_port,
$mail_tp_connection,
$mail_attachments)
;

if ({sc_mail_ok})
{
sc_alert({lang_mail_sended_ok} );
//echo {lang_mail_sended_ok} ;
}
else
{
sc_erro_mensagem({sc_mail_erro});
}

If I comment the message part of code it works so I suppose the error will be there…
How can I show a message that mail was sent successfully ?? or error
I checked also all message in language and they all exist.

/*

if ({sc_mail_ok})
{
sc_alert({lang_mail_sended_ok} );
//echo {lang_mail_sended_ok} ;
}
else
{
sc_erro_mensagem({sc_mail_erro});
}

*/