PDF document in webBrowser control cause 'The memory could not be "read"' error when closing application

I am using a webBrowser control to open PDF document in winforms, it works fine but when closing the ap开发者_StackOverflow社区plication I get sometimes an error : "The Instruction at "0x2d864aa2" referenced memory at "0x00000008". The memory could not be "read". Is there a solution for this problem?

Regards.

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Believe it or not, yesterday I've been banging my head against this exact same problem and here's the solution I've found. Add the following to the FormClosed event:

[DllImport("ole32.dll")]
private static extern void CoFreeUnusedLibraries();

private void MainForm_FormClosed(object sender, FormClosedEventArgs e)
{
    base.OnFormClosed(e);
    webBrowser1.Visible = false;
    while (webBrowser1.IsBusy)
    {
        Application.DoEvents();
    }
    webBrowser1.Dispose();
    CoFreeUnusedLibraries();
}

Actually it seems there's a bug in Adobe Acrobat 9.x causing this exception.