IE7 crashed when RemoveDialogHandler is called - internet-explorer-7

Question

I have this code:
FileDownloadHandler handler = new FileDownloadHandler(fileName);
Browser.AddDialogHandler(handler);
//using (new UseDialogOnce(Browser.DialogWatcher, handler))
//{
Browser.Button(Find.ById("ButtonExportReport")).ClickNoWait();
handler.WaitUntilFileDownloadDialogIsHandled(20);
handler.WaitUntilDownloadCompleted(30);
Console.WriteLine("download finish: " + handler.HasHandledFileDownloadDialog);
//}
Browser.RemoveDialogHandler(handler);
And when I call Browser.RemoveDialogHandler, Internet Explorer 7 crashes with the message:
"no installed debugger has
just_in-time debugging enabled"
(I don't know how to debug IE7 because I only have the CLR debugger which can debug only managed code)
Do you know what I should do ? Any path where I should look for information ?
Thanks
EDIT1:
In fact the error is not caused by the .RemoveDialogHandler
I added
ZvLogManager.Info("start wait");
Thread.Sleep(10000); // wait 10 seconds
ZvLogManager.Info("end wait");
just before the .RemoveDialogHandler, and I get the error message of IE between the "start wait" and "end wait".
So it is file download that makes it crash after 5 seconds. Any idea ?
EDIT 2:
I enable the logging in WatiN and I get:
[Action]: Clicking (no wait) Button 'ButtonExportReport',
[Action]: Clicking on '&Save'
[Action]: Clicking on '&Save'
[Action]: Download started at 4:21:13 PM
[Action]: Clicked Save
[Action]: Saving Download file as c:\temp\export_file634296648679859966.xls
[Action]: Clicking on '&Save'
[Action]: Clicking on 'Close'
[Action]: Download complete at 4:21:17 PM
INFO download finish: True
INFO start wait
INFO end wait
This is not very helpful...

Answer 1

I finally install VS on the server where IE7 was crashing in order to debug IE (!!!). I get an exception: "Unhandled exception in iexplore.exe Access violation reading location"
After googling it, I found this website and it proposes me to reset all settings: Options -> Advanced -> Reset Internet Explorer Settings.
And I have no more crash !