JQuery：$.get 不是函数

I'm having a problem doing something very basic in jQuery. Can someone tell me what I'm doing wrong exactly?

如果我运行下面的代码，函数$.get似乎不见了(getJSON和其他一些也不见了).但是$本身和其他函数确实存在，所以我知道JQuery正在加载.

google.load("jquery", "1.3.2");

function _validate(form, rules_file) {
   $.get('/validation_rules.json',function(data) {
     alert("hello")
   })
} 

任何 idea 都将不胜感激.

谢谢, 抢劫

Edit: here is some additional info:

  <script src="http://www.google.com/jsapi"></script>
  <script>
    google.load("prototype", "1.6");
    google.load("scriptaculous", "1.8");
    google.load("jquery", "1.3.2");
  </script>
  <script>
    jQuery.noConflict(); // prevent conflicts with prototype
  </script>
  <script src="/livepipe/src/livepipe.js"
          type="text/javascript"></script>
  <script src="/livepipe/src/window.js"
          type="text/javascript"></script>
  <script src="/livepipe/src/tabs.js"
          type="text/javascript"></script>
  <script src="/jquery.maskedinput-1.2.2.js"
         type="text/javascript"></script>