embedded font on website won't display in IE or Chrome

[admin]

I have the following font setup in the CSS for a wordpress based site I'm building and the fonts display fine in FF, but not at all in IE(9) or Chrome(latest).

  /* =Typography
  -------------------------------------------------------------- */
  @font-face {
      font-family: 'Humanist';
      src: url('fonts/humanist521lightbt-webfont.eot');
      src: url('fonts/humanist521lightbt-webfont.eot?#iefix') format('embedded-opentype'),
           url('fonts/humanist521lightbt-webfont.woff') format('woff'),
           url('fonts/Humanist521LightBT.ttf') format('truetype'),
           url('fonts/humanist521lightbt-webfont.svg#webfontregular') format('svg');
      font-weight: normal;
      font-style: normal;
  }

  @font-face {
      font-family: 'HumanistIT';
      src: url('fonts/humanist521lightitalicbt-webfont.eot');
      src: url('fonts/humanist521lightitalicbt-webfont.eot?#iefix') format('embedded-opentype'),
           url('fonts/humanist521lightitalicbt-webfont.woff') format('woff'),
           url('fonts/Humanist521LightItalicBT.ttf') format('truetype'),
           url('fonts/humanist521lightitalicbt-webfont.svg#webfontregular') format('svg');
      font-weight: normal;
      font-style: normal;
  }

  @font-face {
     font-family: 'HumanistBo';
     src: url('fonts/humanist777blackbt-webfont.eot');
     src: url('fonts/humanist777blackbt-webfont.eot?#iefix') format('embedded-opentype'),
     url('fonts/humanist777blackbt-webfont.woff') format('woff'),
     url('fonts/Humanist777BlackBT.ttf') format('truetype'),
     url('fonts/humanist777blackbt-webfont.svg#webfontregular') format('svg');
     font-weight: normal;
     font-style: normal;
  }

When I need to use the font for an element, I just add

font-family: 'Humanist', Arial, sans-serif;

The fonts are stored in the theme's directory in folder called "fonts".

Am I doing something wrong or missing something for it to work with other browsers?

Thanks