Difference between CRegKey::QueryStringValue and RegQueryValueEx

When you run this code (on VC++ 7.1 Standard, with _LIBS_USER_FULL_VER defined as "7.10.3077" in atlbuild.h) QueryStringValue will return ERROR_INVALID_DATA and RegQueryValueEx will return 0 (with cbZeroSize = 0). Is there some fix or service pack for this bug, and is it removed from .NET 2005?

#include <windows.h>
#include <atlbase.h>

int _tmain(int argc, TCHAR* argv[])
{
  LONG nRC;
  CRegKey key;
  nRC = key.Create( HKEY_LOCAL_MACHINE, _T("Software\\Testing") );
  nRC = RegSetValueEx( key, _T("ZeroSize"), 0, REG_SZ, NULL, 0 );

  TCHAR szZeroSize[20];
  DWORD cbZeroSize, dwValueType;

  cbZeroSize = sizeof( szZeroSize ) / sizeof( TCHAR );
  nRC = key.QueryStringValue( _T("ZeroSize"), szZeroSize, &cbZeroSize );

  cbZeroSize = sizeof( szZeroSize );
  nRC = RegQueryValueEx( key, _T("ZeroSize"), NULL, &dwValueType,
    (LPBYTE)szZeroSize, &cbZeroSize );

  return 0;
}
.