title: AddPrinterDriver fails with ERROR_ACCESS_DENIED
body: <p>On a few computers a call to AddPrinterDriver fails with ERROR_ACCESS_DENIED. My program is ensured to run with administrator rights, and it copies the driver DLLs into C:\WINDOWS without any errors (access denied or other).</p>
  
  <pre><code>// structure for AddPrinterDriver
  DRIVER_INFO_3 di3 = { 0 };
  di3.cVersion = 3;
  di3.pName = _T(MyAppPrinterName) _T(" Driver");
  di3.pDefaultDataType = _T("");
  // path to driver dll
  FilePath file1(strDriverDirectory.c_str());
  di3.pDriverPath = (LPTSTR) file1.Append(MyAppPrinterDriverDllFileName).ToString();
  // path to driver ui dll
  FilePath file2(strDriverDirectory.c_str());
  di3.pConfigFile = (LPTSTR) file2.Append(MyAppPrinterUiDllFileName).ToString();
  // path to license file
  FilePath file3(strDriverDirectory.c_str());
  di3.pDataFile = (LPTSTR) file3.Append(_T(MyAppPrinterName) _T(".dat")).ToString();
  
  // add driver
  bResult = AddPrinterDriver(NULL, 3, (LPBYTE) &amp;di3);
  StoreLastError(_T("AddPrinterDriver"));
  if (!bResult)
      return FALSE;
  </code></pre>
  
  <p>This is my DrvPrinterEvent function:</p>
  
  <pre><code>BOOL DrvPrinterEvent(
                      LPWSTR  lpwstrPrinterName,
                      INT     iEvent,
                      DWORD   dwFlags,
                      LPARAM  lParam
                      )
  {
      return TRUE;
  }
  </code></pre>