happy new year not apply external font

hello all

first, happy new year

in swishmax actionscript 2 i have this code

PHP Code:

---

onFrame (1) {
    stop();
import TextField.StyleSheet;
this.createTextField("news_txt", 999, 10, 10, 500, 240);
news_txt.multiline = true;
news_txt.wordWrap = true;
news_txt.html = true;
var my_styleSheet:StyleSheet = new StyleSheet();
my_styleSheet.onLoad = function(success:Boolean) {
if (success) {
news_txt.styleSheet = my_styleSheet;
news_txt.htmlText = "<p> hello world<p>"+newline +newline +"<h1>happy new year </h1>";                     
}
};
my_styleSheet.load("my_CSS.css");
} 


---

and the code in the external css file is

PHP Code:

---

p {
text-align: center;
text-decoration: underline;
font-family: Arial;
font-size: 20px;
color: #FF0000;
}
h1 {
text-align: center;
text-decoration: none;
font-family: DIN;
src: url(DIN.ttf);        
font-size: 30px;
color: #0000FF;
font-weight: Regular;

} 


---

but the font not working in my file

how can i solve this problem