Why does this code not work on an UNC directory?. I have a similar FileExist function that works with the same FindFirstFile API call.

Code:
BOOL WINAPI vbDirExist(LPCTSTR lpszDirName)
/*
	Last modified: 19/6/2001.

	Check if a directory exist.
	Returns true if the directory exist, otherwise false.
	To get extended error information, call GetLastError.
	TODO: Doesn't work on network
	
	Parameters ************************************************************
		lpszDirName:		Full directory name
	***********************************************************************
*/
{
	char szBuffer[MAX_PATH];
	WIN32_FIND_DATA tWFD;
	HANDLE hFile = 0;
	DWORD dwError = 0;
	int len = 0;

	// Copy filename to buffer & remove trailing slash
	memset(szBuffer, NULL, MAX_PATH);
	lstrcpy( (LPTSTR)szBuffer, lpszDirName);
	len = lstrlen( (LPTSTR)szBuffer);
	if (szBuffer[len - 1] == '\\')
		szBuffer[len - 1] = '\0';

	hFile = FindFirstFile((LPTSTR)szBuffer, &tWFD);

	//if a valid file handle was returned, and the
	//directory attribute is set the folder exists
	if (hFile != INVALID_HANDLE_VALUE)
	{
		FindClose(hFile);
		return ((tWFD.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == FILE_ATTRIBUTE_DIRECTORY);
	}
	else {
		dwError = GetLastError();
		if (dwError == ERROR_FILE_NOT_FOUND)
			// Clear error
			SetLastError(ERROR_SUCCESS);
		return FALSE;
	}
}