Object doesn't support property or method '

I'm using the selectbox jQuery plugin from http://www.bulgaria-web-developers.com/projects/javascript/selectbox/ .

I also have a linked in js file, which contains the following code:

function loadTeams() {
var responseArray, optionsOutput = '';

$.ajax({
    type: "GET",
    url: "/ajax/team",
    dataType: "json",
    success: function (response) {
        responseArray = response.array;

        for (var i = 0; i < responseArray.length; i++) {
            optionsOutput += '<option value="' + responseArray[i] + '">' + responseArray[i] + '</option>';
        }

        $("#teamSelect").find('option')
                        .remove()
                        .end()
                        .append(optionsOutput);
        $("#teamSelect").selectbox({ speed: 100 });  
    },
    error: function (xhr, ajaxOptions, thrownError) {
        $("#teamSelect").find('option')
        .remove()
        .end()
        .append('<option value=""></option>');
    }
});

}

This works fine in all browsers except IE. In there, I get:

SCRIPT438: Object doesn't support property or method 'selectbox' globals.js, line 38 character 4

That equates to the following line:

$("#teamSelect").selectbox({ speed: 100 });

I've tried even such dramatic and ugly approaches as copying the entire jQuery plugin js file into globals.js, and I still get the error.

What gives?

Edit - Update: I've tried assigning the #teamSelect to a var and calling var.selectbox, but I'm getting the same error.

Aha, the problem was a conflict between jQuery's selectbox plugin (probably jQuery itself) and Foundation 4. When I integrated Foundation 4, I followed the example on their site which had me copy and paste in this cryptic bit:

<script>
    document.write('<script src=' +
    ('__proto__' in {} ? '/js/vendor/zepto' : '/js/vendor/jquery') +
    '.js><\/script>');
</script>

This was loading zepto or jquery, and THEN I was loading jquery from the Google CDN. Removing this line and placing my Google CDN of jQuery first resolved the conflict.