jQuery Errors and Conflict

Hello, I have been having jquery errors on my site for a few months now. It seems whenever I fix one problem something else breaks. The most recent issue is causing me problems with my Gravity Forms plugin. I have already tested for plugin conflicts by disabling all other plugins and this did not resolve the error. This error started when I was working with another plugin author to correct a different jquery error which had followed a jquery error with my theme and so on. I’m not well versed in jquery and so am at a loss as to what to do next.The current error can be found on my site at: http://www.soill.org/athletes-families/form-athlete-interest/ and is listed as Uncaught TypeError: undefined is not a function and reference this line of code:

function gformInitChosenFields(fieldList, noResultsText){
return jQuery(fieldList).each(function(){

var element = jQuery(this);

//only initialize once
if( element.is(“:visible”) && element.siblings(“.chosen-container”).length == 0 ){
var options = gform.applyFilters( ‘gform_chosen_options’, { no_results_text: noResultsText }, element );
element.chosen( options );
}

});
}

Any help that can be provided as to why I am having so many jquery problems would be greatly appreciated. Thanks!