Trouble with RegQueryValueEx()

[HyperEngineer]

I am trying to extract a register value. This is my code:
@
int QEnumerator::getDeviceInfo(HDEVINFO hDevInfo,
QSerialPortInfo *portInfo,
PSP_DEVINFO_DATA portInfoData)
{
QString friendName;
QString phyName;
QString enumName;
QString hardwareID;
QString vid;
QString pid;
QString portName;
QString msg;

// Get device information.
friendName = getDeviceProperty(hDevInfo, portInfoData, SPDRP_FRIENDLYNAME);
portInfo->SetFriendName(friendName);
phyName = getDeviceProperty(hDevInfo, portInfoData, SPDRP_PHYSICAL_DEVICE_OBJECT_NAME);
portInfo->SetPhyName(phyName);
enumName = getDeviceProperty(hDevInfo, portInfoData, SPDRP_ENUMERATOR_NAME);
portInfo->SetEnumName(enumName);
hardwareID = getDeviceProperty(hDevInfo, portInfoData, SPDRP_HARDWAREID);

• // This does not appear to work.
  // Get the port name from the registry.
  HKEY devKey = SetupDiOpenDevRegKey(hDevInfo,
  portInfoData,
  DICS_FLAG_GLOBAL,
  0,
  DIREG_DEV,
  KEY_READ);
  if(NULL != devKey)
  {
  portName = getRegKeyValue(devKey, (LPCTSTR)("Port Name"));
  portInfo->SetPortName(portName);
  }
  else
  QMessageBox::information(NULL, "Reg Key", "No key handle");

• // Get the PID and VID from the hardware ID.
  QRegExp regExpHWID("VID_(\w+)&PID_(\w+)");
  if(hardwareID.toUpper().contains(regExpHWID))
  {
  vid = regExpHWID.cap(1);
  portInfo->SetVendorID(vid);
  pid = regExpHWID.cap(2);
  portInfo->SetProductID(pid);
  }

  return 0;
  }

QString QEnumerator::getRegKeyValue(HKEY devKey, LPCTSTR property)
{
// Get the key value of the property.
QString result;
DWORD size = -1;
DWORD type;
DWORD i;
DWORD ret;
QString msg;

// Get the size of the returned buffer.
RegQueryValueEx(devKey, property, NULL, NULL, NULL, &size);
BYTE *buff = new BYTE[size];

msg.sprintf("size = %ld", size);
QMessageBox::information(NULL, "Key Value", msg);

ret = RegQueryValueEx(devKey, property, NULL, &type, buff, &size);
if(ret == ERROR_SUCCESS)
{
    result.clear();
    for(i = 0; i < size; i++)
    {
        if('\0' == (char)buff[i])
           continue;
        else
           result.append((char)(buff[i]));
    }
    result.append('\0');
}
else if(ERROR_MORE_DATA == ret)
    QMessageBox::information(NULL, "Reg Query", "More data.");
else if(ERROR_FILE_NOT_FOUND == ret)
    QMessageBox::information(NULL, "Reg Query", "File not found");
else if(ERROR_NOACCESS == ret)
{
    QMessageBox::information(NULL, "Reg Query", "No access.");
}

RegCloseKey(devKey);
delete [] buff;

return result;

}
@

What I get back from the RegQueryValueEx function is ERROR_NOACCESS.
Opening the key with KEY_READ combines KEY_QUERY_VALUE, STANDARD_RIGHTS_READ,
KEY_ENUMERATE_SUB_KEYS and KEY_NOTIFY. I did try using just KEY_QUERY_VALUE with
the same results.

I can go into the registry, manually, and find the value I am looking for and it is there.

I'm using Qt4.8.1 in Netbeans 7.2.1.
I'm running Windows Vista Home Premium.

Thanks,
DCM