IHTMLDocument2/IHTMLElement2 functions crash in IE7(Access violation) when scrolling

PROBLEM

1. How do i programmatically scroll an IWebBrowser2 control in all IE versions?

2. Why is it that the code i have runs in IE6 but crashes in IE7?

3. Follow-up to question(2), is there a way to work around the Access Violation in mshtml.dll when calling functions from the IHTMLWindow2, IHTMLElement2, IHTMLDocument2 and IHTMLDocument3? (ex. get_scrollTop, get_scrollHeight, get_ScrollWidth, get_parentWindow)

THANKS!


CODE

Code:

//error trapping had been removed
BOOL CBrowserControl::Scroll(LONG scrollType)
{
CComPtr<IDispatch> spDoc;
long scrollPos;

m_spWebBrowser->get_Document(&spDoc);

IHTMLDocument2 *pDocument = NULL;
HRESULT hresult = spDoc->QueryInterface( IID_IHTMLDocument2, (void**)&pDocument );
//hresult is S_OK
IHTMLElement *pBody = NULL;
hresult = pDocument->get_body( &pBody );
IHTMLTextContainer *pElement = NULL;
hresult = pBody->QueryInterface(IID_IHTMLTextContainer,(void**)&pE lement);
//hresults are S_OK

IHTMLWindow2 *pWindow = NULL;
hresult = pDocument->get_parentWindow( &pWindow ); 
//the crash happens here. cannot read hresult anymore since an access violation happens upon calling the function

long scrollwidth, scrollheight;
pElement->get_scrollHeight(&scrollheight); 
//a crash here occurs too if i try to comment the code above
pElement->get_scrollWidth(&scrollwidth);
//still crashes here

long page; 
m_spWebBrowser->get_Height(&page);

switch(scrollType)
{
case StepDown:
............//other cases here
}
pWindow->scrollBy( 0, scrollPos );
return true;
}

DETAILS

Good day..

I know it's quite a long shot, but I have this problem.. And I've ran out of places to ask for help for..

I am supposed to make my webbrowser control scroll depending on what scrollType I pass. Well, everything worked fine... that is, in IE6.
My code crashes in IE7 at get_parentWindow, get_scrollHeight (and perhaps also in scrollBy). They all return access violations.

Trying other solutions on the net didn't help, IE7 still crashes with calling functions (like get_scrollTop and etc)... I already tried scrolling using IHTMLElement2. But no luck... I also tried IHTMLDocument3->get_documentElement and used that for scrolling, still... no sunshine in sight.

Is this an IE thing? or are there settings I failed to look at? Does anyone know by chance a way to work around this? it's really not good to just restrict users from using my scrolling functions if they don't use ie6.

i am kinda desperate now.
will be forever grateful for the help.

ultimately, i gave up on this idea.



instead of using the interfaces and so on as what i've done, i just focused to the control and automatically sent the keyboard keys.