Problem with CreateWindowEx

Hi!

I'm developing a function for a Windows Mobile 5 device, which should display a window and draw some stuff in it. The function is in a DLL which is called repeatedly during the execution of the program. The first, second and third time the function runs, everything works as it should, but from the fourth time and on, no window is displayed.

Calling GetLastError after CreateWindowEx, says the error ERROR_ACCESS_DENIED occured. The message loop aborts immediatelly, and no WM_PAINT event occurs.

Can anyone see what may be causing this?

Thanks!


#include <stdafx.h>

#include <windows.h>
#include <commctrl.h>

static LPCWSTR g_szClassName = _T("Name");

static LRESULT CALLBACK WndProc (HWND hwnd , UINT msg,WPARAM wParam , LPARAM lParam);

static BOOL bsRunning = FALSE;
static UINT nTimerEvent = NULL;

BOOL doCmd(PTCHAR* cmdArgs, DWORD countArgs, PTCHAR* cmdReply, HINSTANCE hInstance)
{
      iAngle = _wtoi(cmdArgs[0]);
      iSpacing = _wtoi(cmdArgs[1]);

      if(!bsRunning)
      {
            bsRunning = TRUE;
            
            WNDCLASS wc;

            wc.style  = 0;
            wc.lpfnWndProc = WndProc;
            wc.cbClsExtra  = 0;
            wc.cbWndExtra  = 0;

            wc.hInstance   = hInstance;
            wc.hIcon       = LoadIcon(NULL,NULL);
            wc.hCursor     = LoadCursor(NULL,IDC_ARROW);

            wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
            wc.lpszMenuName  = NULL;
            wc.lpszClassName = g_szClassName;

            if(!RegisterClass(&wc))
            {
                  *cmdReply = _T("Failed to create window");
                  return FALSE;
            }

            HWND hwnd;
            hwnd = CreateWindowEx(WS_EX_DLGMODALFRAME, g_szClassName, g_szClassName, WS_DLGFRAME | WS_VISIBLE, 0, 0, 240, 320, NULL, NULL, hInstance, NULL);

            if(hwnd == NULL)
             {
                     *cmdReply = _T("Failed to create window");
                     return FALSE;
             }

            nTimerEvent = SetTimer(hwnd,1000,2000,NULL);
            
            MSG Msg;

            while(GetMessage(&Msg,hwnd,0,0))
            {
                                   TranslateMessage(&Msg);
                  DispatchMessage (&Msg);
            }

            UnregisterClass(g_szClassName, hInstance);

            *cmdReply = _T("OK\0");
            return TRUE;
      }
      return FALSE;
}

static void DrawTest(HWND hwnd)
{
      PAINTSTRUCT paintStruct;
      HDC hDC;
      hDC = BeginPaint(hwnd,&paintStruct);

// Drawing here...
      
      EndPaint(hwnd, &paintStruct);
}

LRESULT CALLBACK WndProc (HWND hwnd , UINT msg,WPARAM wParam , LPARAM lParam)
{
      DWORD dwState;

      switch(msg)
      {      
            case WM_CLOSE:
                  DestroyWindow  (hwnd);
                  break;
            case WM_PAINT:
                  DrawTest(hwnd);
                  break;
            case WM_DESTROY:
                  PostQuitMessage(0);
                  break;
            case WM_TIMER:
                  KillTimer(hwnd,nTimerEvent);
                  DestroyWindow(hwnd);
                  break;
            default:
                  return DefWindowProc(hwnd,msg,wParam,lParam);
        }
        return 0;
}