Windows Phone application-error on calling Google Map API's

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C#

Javascript

Mobile

Google-Maps

I am trying to use Google Map Api's; trying to call javaScripts from Windows Phone 7 application ; script file is in xmlfile.html in project

public MainPage()
{
    InitializeComponent();

          
    Loaded += new RoutedEventHandler(MainPage_Loaded);

    webBrowser1.Loaded += (object sender, RoutedEventArgs e) =>;
    { webBrowser1.InvokeScript("initialize"); };

At the last line, while calling the initialize function, I've got the error "An unknown error has occurred". Error: 8000FFFF.

I am newbie to developing phone applications and I don't know if this code is true way or there is more that I need to do? Thanks for any help.
Sorry for bad english