How does shadowVariable work for member variables?

[Sander Bouwhuis]

I get the following error for my code:
Id: shadowVariable
CWE: 398
Local variable 'm_u64TickCountStart' shadows outer variable

m_u64TickCountStart is a member variable of my CLauncher class.
This is my code:

// This functions shows the dialog
void CLauncher::ShowDialog(std::wstring *pWstrDebugLog, HINSTANCE hInst, bool bForceNewLicense, const CCmdLineParams &cmdLineParams)
{
  // Set the debug log
  m_pWstrDebugLog = pWstrDebugLog;

  ENTER_FUNCTION_DEBUG_LOG_TO_MEM

  try
  {
    CHECK_MEM_LEAKS

    // Initialize the variables
    m_u64TickCountStart = GetTickCount64();

    // ...
  }
  catch(...) { OnException(m_pWstrDebugLog, __FILE__, __LINE__, __FUNCSIG__, __TIMESTAMP__, nullptr); }
}

What does the error signify? What am I doing wrong?

[CHR]

Please post a self-contained example which reproduces the issue.
How is m_u64TickCountStart declared? Are those macros like CHECK_MEM_LEAKS defined/visible to cppcheck?