Javascript Undefined Function Errors

Javascript Undefined Function Errors

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I'm getting these errors on the video page on my site. They are preventing
my videos from loading and changing to one another. I have very little
experience with javascript so I would appreciate any help.
jquery.coda-slider-2.0.js:12TypeError: 'undefined' is not a function
(evaluating '$')
menu.js:12TypeError: 'undefined' is not a function (evaluating
'$(document)')
videos:365TypeError: 'undefined' is not a function (evaluating
'$(function(){
// Accordion
$(".accordion").accordion({
header: ".AccordionHeader",
autoHeight: false
});
})')
videos:379TypeError: 'undefined' is not a function (evaluating
'$(function() {
$( ".tabs" ).tabs();
})')
videos:393TypeError: 'undefined' is not a function (evaluating
'$(function() {
$( ".dialog" ).dialog();
})')