You may have a problem with this due to the operating system and Internet Browser you are using.

One easy way of getting round this is by using a JQuery library called Uniform. It allows you to style form elements how you want and is cross-browser compatible.

You can find more information on this here: http://uniformjs.com/.

I hope that helps.

Have you tried to debug that in firebug?

How about making the backgrounds important?

form#contact input[type="text"], input[type="url"], 

    input[type="email"], input[type="tel"], textarea, select {
        margin: 3px 0 0 0;
        padding: 6px; 
        width: 260px; 
        font-family: arial, sans-serif; 
        font-size: 12px; 
        border: 1px solid #ccc;
        background: -webkit-gradient(linear, left top, left 15, from(#FFFFFF), color-stop(4%, #f4f4f4), to(#FFFFFF)) !important;
        background: -moz-linear-gradient(top, #FFFFFF, #f4f4f4 1px, #FFFFFF 15px) !important;
    }