What's wrong with the following code?

#include "stdafx.h"
#include "resource.h"
#include <stdio.h>
#include <windows.h>
BOOL CALLBACK DlgProc(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam);
int APIENTRY WinMain(HINSTANCE hInstance,
					 HINSTANCE hPrevInstance,
					 LPSTR     lpCmdLine,
					 int       nCmdShow)
{
	// TODO: Place code here.
	DialogBox(hInstance, MAKEINTRESOURCE(IDD_DIALOG1), NULL, DlgProc);
	return 0;
}
BOOL CALLBACK DlgProc(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
	const char szDlgTitle[] = "RecvMessage";
	static HWND s_hEditShowRecv;

	switch (message)
	{
	case WM_INITDIALOG:
		SetWindowTextA(hDlg, szDlgTitle);
		s_hEditShowRecv = GetDlgItem(hDlg, IDC_EDIT_RECVMESSAGE);
		return TRUE;

	case WM_COMMAND:
		switch (LOWORD(wParam))
		{
		case IDOK:
		case IDCANCEL:
			EndDialog(hDlg, LOWORD(wParam));
			return TRUE;
		}
		break;

	case WM_COPYDATA:
		{
			COPYDATASTRUCT *pCopyData = (COPYDATASTRUCT*)lParam;
			char szBuffer[300];

			memset(szBuffer, 0, sizeof(szBuffer));
			sprintf(szBuffer, "dwData:%d cbData:%d\r\nlpData:0x%08x = %s\r\n\r\n", 
				pCopyData->dwData, pCopyData->cbData, 
				(PVOID)pCopyData->lpData, (char*)pCopyData->lpData);
			//在编辑框中追加数据
			SendMessage(s_hEditShowRecv, EM_SETSEL, (WPARAM)-1, (LPARAM)-1); // (0, -1)表示全选, (-1，任意)表示全不选
			SendMessage(s_hEditShowRecv, EM_REPLACESEL, FALSE, (LPARAM)szBuffer);
			SendMessage(s_hEditShowRecv, EM_SCROLLCARET, 0, 0);
		}
		return TRUE;
	}
	return FALSE;
}