what is problem of this code? dont work in fire fox onlu

@font-face
{
font-family: 'B Yekan';
src: url('../../../DirFont/Yekan.eot?#') format('eot'),
url('../../../DirFont/Yekan.woff') format('woff'),
url('../../../DirFont/Yekan.ttf') format('truetype');
}

body
{
font-family:'B Yekan' ,BYekan,Arial, Helvetica, sans-serif;
margin: 0;
padding: 0;
color: #666;

font-size: 12px;
line-height: 1.5em; 
background-color: #eeeff3; background-repeat: repeat-x; background-position: top

}