Strange maxDate in datePicker

Strange maxDate in datePicker

Hi,

For some reason I keep getting an Invalid Date reported for the datePicker I use. Been staring at it for days now and I simply don't see it. 
I have the following rather simple code in my application:

$(document).ready(function(){
$.get('getmaxdate', function(data){
var maxDate = new Date(Date.parse(data));
$( "#blogDate" ).datepicker({ dateFormat: "dd-mm-yy", constrainInput: true, showAnim: "fade", 
maxDate: maxDate});
});
});

As you can see in the screenshot of Firebug below the data coming in (from an Ajax-request to a PHP-page is a straightforward date as a string. And this string is successfully converted to a Date-object. But this always ends with a datePicker that states that the maxDate is an invalid Date. And therefore the maxDate does not do its trick.

Beats me. Any help is appreciated