为什么执行了下面的块输出代码后,重启就不能加载USB程序了?

驱动是用ddk+vc6.0,用的是块管道1做控制管道,当执行完CloseHandle (hDevice)后,再重启动,在设备管理器中,就看到了小红叉,只有断电.
BOOL BulkOut()
{
HANDLE  hDevice = NULL;
BOOL bResult;
BULK_TRANSFER_CONTROL bulkControl;
ULONG ulBytes = 0;
if( FALSE == OpenDriver( hDevice, "Ezusb-0" ) )
return FALSE;
bulkControl.pipeNum = 1;
bResult = DeviceIoControl( hDevice, IOCTL_EZUSB_BULK_WRITE,
& bulkControl, sizeof( BULK_TRANSFER_CONTROL ),      pchCommand, BULK_PACKET_SIZE, & ulBytes, NULL );
CloseHandle (hDevice);
return bResult;
}