Texture mapping problem

#include <windows.h>
#include <d3d9.h>
#include <d3dx9.h>
#define RELEASE(x) { if(x) { (x)->Release(); (x)=NULL; } }

HINSTANCE hInst;
HWND wndHandle;

bool initWindow(HINSTANCE hInstance);
LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);


struct D3DVERTEX
{
	float x, y, z, rhw;
	float tu, tv;
};
const DWORD vertex_fvf = D3DFVF_XYZRHW | D3DFVF_TEX1;

LPDIRECT3D9 pD3D;
LPDIRECT3DDEVICE9 pd3dDevice;
LPDIRECT3DTEXTURE9 Background;

D3DVERTEX vBackground[] = {
	{0,0,0,1,0,0}, {640,0,0,1,1,0}, {640,480,0,1,1,1}, {0,480,0,1,0,1}
};


bool initD3D(int,int,D3DFORMAT,bool);
void Render();

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow)
{
	if(!initWindow(hInstance))
		return false;
	if(!initD3D(640,480,D3DFMT_UNKNOWN,false))
		return false;

	D3DXCreateTextureFromFileEx(pd3dDevice,
								"background.bmp",
								640,
								480,
								1,
								0,
								D3DFMT_X8R8G8B8,
								D3DPOOL_MANAGED,
								D3DX_FILTER_NONE,
								D3DX_DEFAULT,
								NULL,
								NULL,
								NULL,
								&Background);
	
	pd3dDevice->SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_SELECTARG1);
	pd3dDevice->SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TEXTURE);
	pd3dDevice->SetTextureStageState(0, D3DTSS_COLORARG2, D3DTA_DIFFUSE);


	MSG msg;
	ZeroMemory(&msg, sizeof(msg));
	while(msg.message!=WM_QUIT)
	{
		if(PeekMessage(&msg,NULL,0,0,PM_REMOVE))
		{
			TranslateMessage(&msg);
			DispatchMessage(&msg);
		}
		else
		{
			Render();
		}
	}

	RELEASE(Background);
	RELEASE(pd3dDevice);
	RELEASE(pD3D);

	return (int)msg.wParam;
}

bool initWindow(HINSTANCE hInstance)
{
	WNDCLASSEX wcex;
	
	wcex.cbSize			= sizeof(WNDCLASSEX);
	wcex.style			= CS_HREDRAW | CS_VREDRAW;
	wcex.lpfnWndProc	= (WNDPROC)WndProc;
	wcex.cbClsExtra		= 0;
	wcex.cbWndExtra		= 0;
	wcex.hInstance		= hInstance;
	wcex.hIcon			= 0;
	wcex.hCursor		= LoadCursor(NULL, IDC_ARROW);
	wcex.hbrBackground	= (HBRUSH)(COLOR_WINDOW+1);
	wcex.lpszMenuName	= NULL;
	wcex.lpszClassName	= "DirectXExample";
	wcex.hIconSm		= 0;
	RegisterClassEx(&wcex);

	wndHandle = CreateWindow("DirectXExample", 
							 "DirectXExample", 
							 WS_EX_TOPMOST | WS_POPUP | WS_VISIBLE,
							 CW_USEDEFAULT, 
							 CW_USEDEFAULT, 
							 640, 
							 480, 
							 NULL, 
							 NULL, 
							 hInstance, 
							 NULL);
	if(!wndHandle)
		return false;

	ShowWindow(wndHandle, SW_SHOW);
	UpdateWindow(wndHandle);
	return true;
}

bool initD3D(int bbWidth, int bbHeight, D3DFORMAT bbFormat, bool Fullscreen)
{
	pD3D = Direct3DCreate9( D3D_SDK_VERSION );
	D3DPRESENT_PARAMETERS d3dpp;
	{
		ZeroMemory( &d3dpp, sizeof(d3dpp) );
		d3dpp.Windowed = !Fullscreen;
		d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
		d3dpp.BackBufferFormat = bbFormat;
		d3dpp.BackBufferCount  = 1;
		d3dpp.BackBufferHeight = bbHeight;
		d3dpp.BackBufferWidth  = bbWidth;
		d3dpp.hDeviceWindow    = wndHandle;
	}

	if( FAILED (pD3D->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_REF, wndHandle,
		D3DCREATE_SOFTWARE_VERTEXPROCESSING, &d3dpp, &pd3dDevice) ) )
		return false;

	pd3dDevice->SetRenderState(D3DRS_LIGHTING, FALSE);
	pd3dDevice->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
	pd3dDevice->SetRenderState(D3DRS_DESTBLEND,D3DBLEND_INVSRCALPHA);
	pd3dDevice->SetRenderState(D3DRS_ALPHABLENDENABLE,TRUE);

	return true;

}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	switch(message)
	{
	case WM_KEYDOWN:
		switch(wParam)
		{
		case VK_ESCAPE:
			PostQuitMessage(0);
			break;
		}
		break;
	case WM_DESTROY:
		PostQuitMessage(0);
		break;
	}

	return DefWindowProc(hWnd, message, wParam, lParam);
}

void Render()
{
	pd3dDevice->SetFVF(vertex_fvf);
	pd3dDevice->BeginScene();
	pd3dDevice->Clear(0, NULL, D3DCLEAR_TARGET, 0xFF0000FF, 1.0f, 0);

	pd3dDevice->SetTexture(0, Background);
	pd3dDevice->DrawPrimitiveUP(D3DPT_TRIANGLEFAN, 2, vBackground, sizeof(D3DVERTEX));

	pd3dDevice->EndScene();
	pd3dDevice->Present(NULL, NULL, NULL, NULL);
}