Error in Annotated Timeline: "Object Date(...) has no method getTime" #25

What steps will reproduce the problem?
1. I've created an annotated timeline using a json wire source
2. After the annotatedtimeline.draw method is called, the type error occurs
3. This is the error output from Chrome. Other browsers have slightly different 
error messages.

What is the expected output? What do you see instead?
Expected would be a working timeline chart. Instead, An alert pops up with the 
above error. If I send this exact dataset to a Visualization LineChart, it 
works fine.

What version of the product are you using? On what operating system?
        google.load("visualization", '1', { packages: ['corechart'] });
        google.load('visualization', '1', { packages: ['annotatedtimeline'] });
This is running on Vista and Windows 7, but the same happens on the deployed 
version on a Windows Server.
It fails on Chrome, Firefox, IE, Safari


Please provide any additional information below.
Following is the method that calls the timeline chart. You'll notice that I've 
commented out a call to a LineChart using the same date. The LineChart works 
fine, but the annotated timeline produces the error.

function drawPercentSpentOverTime(gridTableData) {
        try {
            var chartDiv = $("#PercentSpentOverTimeChart").get(0);
            //var timeline = new google.visualization.LineChart(chartDiv);
            var annotatedtimeline = new google.visualization.AnnotatedTimeLine(chartDiv);
            annotatedtimeline.draw(gridTableData,
            {
                fontSize: 10,
                fontName: "Calibri",
                legendFontSize: 12,
                curveType: 'function',
                width: 920,
                hAxis: {title: 'Date', titleTextStyle: {fontSize: 12}},
                vAxis: { title: 'Percent', titleTextStyle: { fontSize: 12} },
                colors: ['#B98332','#FFCC33','#FF9900', '#344368', '#577647', '#871B3C' ]
            });
        }
        catch (e) {
            alert(e);
        }
    }


Below is the Json returned from the server. This was copied directly from 
firebug:

{"status":"ok","reqId":0,"table":{"cols":[{"id":"ActualsDate","label":"Date","ty
pe":"date"},{"id":"PercentSpent","label":"Percent Of Budget 
Spent","type":"number"},{"id":"TimeElapsed","label":"Percent Time 
Elapsed","type":"number"}],"rows":[{"c":[{"v":"Date(2010,7,23)","f":"2010-Aug-23
"},{"v":0.241758227,"f":"0.2 %"},{"v":17.9419537,"f":"17.9 
%"}]},{"c":[{"v":"Date(2010,7,24)","f":"2010-Aug-24"},{"v":0.483516455,"f":"0.5 
%"},{"v":18.2058048,"f":"18.2 
%"}]},{"c":[{"v":"Date(2010,7,25)","f":"2010-Aug-25"},{"v":0.725274742,"f":"0.7 
%"},{"v":18.4696579,"f":"18.5 
%"}]},{"c":[{"v":"Date(2010,7,26)","f":"2010-Aug-26"},{"v":0.9670329,"f":"1.0 
%"},{"v":18.73351,"f":"18.7 
%"}]},{"c":[{"v":"Date(2010,7,27)","f":"2010-Aug-27"},{"v":1.20879126,"f":"1.2 
%"},{"v":18.99736,"f":"19.0 
%"}]},{"c":[{"v":"Date(2010,7,28)","f":"2010-Aug-28"},{"v":1.45054948,"f":"1.5 
%"},{"v":19.2612133,"f":"19.3 
%"}]},{"c":[{"v":"Date(2010,7,29)","f":"2010-Aug-29"},{"v":1.69230771,"f":"1.7 
%"},{"v":19.5250664,"f":"19.5 
%"}]},{"c":[{"v":"Date(2010,7,30)","f":"2010-Aug-30"},{"v":1.98901093,"f":"2.0 
%"},{"v":19.7889175,"f":"19.8 
%"}]},{"c":[{"v":"Date(2010,7,31)","f":"2010-Aug-31"},{"v":2.28571415,"f":"2.3 
%"},{"v":20.05277,"f":"20.1 
%"}]},{"c":[{"v":"Date(2010,8,1)","f":"2010-Sep-01"},{"v":2.58241773,"f":"2.6 
%"},{"v":20.3166237,"f":"20.3 
%"}]},{"c":[{"v":"Date(2010,8,2)","f":"2010-Sep-02"},{"v":2.879121,"f":"2.9 
%"},{"v":20.5804749,"f":"20.6 
%"}]},{"c":[{"v":"Date(2010,8,3)","f":"2010-Sep-03"},{"v":3.17582417,"f":"3.2 
%"},{"v":20.844326,"f":"20.8 
%"}]},{"c":[{"v":"Date(2010,8,4)","f":"2010-Sep-04"},{"v":3.4725275,"f":"3.5 
%"},{"v":21.10818,"f":"21.1 
%"}]},{"c":[{"v":"Date(2010,8,5)","f":"2010-Sep-05"},{"v":3.76923084,"f":"3.8 
%"},{"v":21.3720322,"f":"21.4 
%"}]},{"c":[{"v":"Date(2010,8,6)","f":"2010-Sep-06"},{"v":3.86813164,"f":"3.9 
%"},{"v":21.6358833,"f":"21.6 
%"}]},{"c":[{"v":"Date(2010,8,7)","f":"2010-Sep-07"},{"v":3.967033,"f":"4.0 
%"},{"v":21.8997364,"f":"21.9 
%"}]},{"c":[{"v":"Date(2010,8,8)","f":"2010-Sep-08"},{"v":4.065934,"f":"4.1 
%"},{"v":22.1635876,"f":"22.2 
%"}]},{"c":[{"v":"Date(2010,8,9)","f":"2010-Sep-09"},{"v":4.164835,"f":"4.2 
%"},{"v":22.42744,"f":"22.4 
%"}]},{"c":[{"v":"Date(2010,8,10)","f":"2010-Sep-10"},{"v":4.26373625,"f":"4.3 
%"},{"v":22.6912937,"f":"22.7 
%"}]},{"c":[{"v":"Date(2010,8,11)","f":"2010-Sep-11"},{"v":4.362637,"f":"4.4 
%"},{"v":22.9551449,"f":"23.0 
%"}]},{"c":[{"v":"Date(2010,8,12)","f":"2010-Sep-12"},{"v":4.46153831,"f":"4.5 
%"},{"v":23.218996,"f":"23.2 
%"}]},{"c":[{"v":"Date(2010,8,13)","f":"2010-Sep-13"},{"v":4.53846169,"f":"4.5 
%"},{"v":23.482851,"f":"23.5 
%"}]},{"c":[{"v":"Date(2010,8,14)","f":"2010-Sep-14"},{"v":4.61538458,"f":"4.6 
%"},{"v":23.7467022,"f":"23.7 
%"}]},{"c":[{"v":"Date(2010,8,15)","f":"2010-Sep-15"},{"v":4.692308,"f":"4.7 
%"},{"v":24.0105534,"f":"24.0 
%"}]},{"c":[{"v":"Date(2010,8,16)","f":"2010-Sep-16"},{"v":4.769231,"f":"4.8 
%"},{"v":24.2744064,"f":"24.3 
%"}]},{"c":[{"v":"Date(2010,8,17)","f":"2010-Sep-17"},{"v":4.857143,"f":"4.9 
%"},{"v":24.53826,"f":"24.5 
%"}]},{"c":[{"v":"Date(2010,8,18)","f":"2010-Sep-18"},{"v":4.95604372,"f":"5.0 
%"},{"v":24.80211,"f":"24.8 
%"}]},{"c":[{"v":"Date(2010,8,19)","f":"2010-Sep-19"},{"v":5.054945,"f":"5.1 
%"},{"v":25.0659637,"f":"25.1 
%"}]},{"c":[{"v":"Date(2010,8,20)","f":"2010-Sep-20"},{"v":5.13186836,"f":"5.1 
%"},{"v":25.3298168,"f":"25.3 %"}]}]}}