access conflict with (LPVOID)this in CreateWindowEx

This makes me very puzzled and angry.Please have a look at :
......
......
_hSelf=::CreateWindowEx(
WS_EX_ACCEPTFILES,
(LPCWSTR)_className,\
(LPCWSTR)"Web Studio 2008",\
WS_OVERLAPPEDWINDOW,\
CW_USEDEFAULT,\
CW_USEDEFAULT,\
CW_USEDEFAULT,\
CW_USEDEFAULT,\
_hParent,\
NULL,\
_hInst,\
(LPVOID)this);
.......
.......
The code is compiled and linked successly under VS2005.But ever time
it runs to "(LPVOID)this" in the function "CreateWindowEx" ,an
exception occurs which say
0x00000000 Department untreated anomaly: 0xC0000005: reading position
0 x00000000 visit when conflict
in the VS 2005.

Oh,I'm sorry I'm new to this usernet.I think the bug concerned with
cpp,so...And if it can't be solved here ,I will go windows programming
NG. But please do me a favor, thanks.
.....
class WebStudio:public Window
{
public:
WebStudio():Window(){};
//,_mainWindowStatus(0),_pMainSplitter(NULL),_hTabPo pupMenu(NULL),_hTabPopupDropMenu(NULL),_pEditView( NULL),_pDocTab(NULL)
{};
>
void init(HINSTANCE,HWND,const char*);
bool doOpen(const char *fileName);
static const char * getClassName() {
return _className;
};
private:
static const char _className[32];
};
....
class Window
{
public:
Window():_hSelf(NULL),_hParent(NULL),_hInst(NULL){ };
virtual ~Window(){};
virtual void init(HINSTANCE hInst, HWND parent)
{
_hInst = hInst;
_hParent = parent;
}
>
protected:
HINSTANCE _hInst;
HWND _hParent;
HWND _hSelf;
};
....

Mm,after I send the last message,I suddenly notice that the last param
in CreateWindowEx should point to a CREATESTRUCT struct.But if so, I
have no idea to make it point to the CREATESTRUCT struct.How to do
that?

I did that,such as:
....
CREATESTRUCT p;
p.cx=0;
p.cy=0;
p.dwExStyle=0;
p.hInstance=hInst;
p.hMenu=NULL;
p.hwndParent=NULL;
p.lpCreateParams=NULL;
p.lpszClass=(LPCWSTR)_className;
p.lpszName=TEXT("SB");
p.style=NULL;
p.x=0;
p.y=0;
_hSelf=::CreateWindowEx(
WS_EX_ACCEPTFILES,\
(LPCWSTR)_className,\
(LPCWSTR)"Web Studio 2008",\
WS_OVERLAPPEDWINDOW,\
CW_USEDEFAULT,\
CW_USEDEFAULT,\
CW_USEDEFAULT,\
CW_USEDEFAULT,\
_hParent,\
NULL,\
_hInst,\
(LPVOID)&p);
....
But the same conflict still exists.
Where's the problem ??