Use your developer tools to make sure the fontawesome font file and fontawesome css loaded. Make sure they are there and there were no errors serving them.

Also note that there's no IE 7 support...

+++ Rick ---

>Hi everybody,
>
>This is what I see when I inspect the element:
>

><div class="alert alert-danger">
>                                <i class="fa fa-exclamation-circle fa-2x"></i>
>                                Username or Password is incorrect.
>                            </div>

>
>However, I do not see the icon at all and I see it 0px * 0px. Do you know what is wrong in this markup and why I don't see the error sign?
>
>Thanks in advance.