I´ve found out, that the form is also not showing the GETTEXT message after submit. It´s on line 23.
_e("Your message was successfully sent.", "smcf");
So, there is some strange behavior related to XmlHttpRequest, JQuery or something like that. Nothing related to PHP itself, DNS, server issue etc. The point is maybe that I have different plugins installed and also using some jquery, the same theme have own jquery, there is also some calendar using XML HTTP request...
I´m quite new to WordPress and don´t know how are these conflicts between more jquery.js files solved. That´s bit confusing... why are those plugins each time using their own jquery and there is not any verification about existing and already included js file. But it is up to developers and also user...
Hope I´ll find where´s the conflict between included javascript files.
Stan