I am not sure if this is the case, but please note that IE only supports .eot (Embedded OpenType) fonts and the fonts you have hosted will not work in Internet Explorer. Not sure if this is your problem but it is a possible problem with your code.
The way to fix this is to use a font converter. One I have used in the past is http://www.fontsquirrel.com/tools/webfont-generator. Then call both the EOT and TTF fonts within your CSS file. I have provided an example below.
@font-face {
font-family: Acme;
src: url('fonts/eot/Acme-Regular.eot'),
url('fonts/ttf/Acme-Regular.ttf');
}
If this is not the problem, I took a look at your code and I cannot find on the live site where in your CSS you actually called the @font-face command and as per the comments above I am also getting a 500 error when trying to access the fonts on your server.
Another option is to use the Google Web Fonts Library which are hosted on Google's servers and can be called remotely by your code http://www.google.com/webfonts.