If you are using CodeIgniter under IIS7 :
In your web.config file, add woff to the pattern
<rule name="Rewrite CI Index">
<match url=".*" />
<conditions>
<add input="{REQUEST_FILENAME}" pattern="css|js|jpg|jpeg|png|gif|ico|htm|html|woff" negate="true" />
</conditions>
<action type="Rewrite" url="index.php/{R:0}" />
</rule>
Hope it helps !