I get this errors in my gentoo amd64 system:

if g++ -DHAVE_CONFIG_H -I. -I. -I../../src/Include -I../.. -I../../src  -I/home/edi/games/fgfs/cvs/osg/OSG_OP_OT-1.2-Flightgear/OpenSceneGraph/include -I/usr/X11R6/include -I/usr/local/include  -g -O2 -D_REENTRANT -MT AIMgr.o -MD -MP -MF ".deps/AIMgr.Tpo" -c -o AIMgr.o AIMgr.cxx; \
        then mv -f ".deps/AIMgr.Tpo" ".deps/AIMgr.Po"; else rm -f ".deps/AIMgr.Tpo"; exit 1; fi
AIMgr.cxx: In member function 'virtual void FGAIMgr::init()':
AIMgr.cxx:84: error: no match for 'operator=' in '((FGAIMgr*)this)->FGAIMgr::_defaultModel = sgLoad3DModel(((const std::string&)((const std::string*)globals-> FGGlobals::get_fg_root())), ((const std::string&)(& std::basic_string<char, std::char_traits<char>, std::allocator<char> >(planepath. std::basic_string<_CharT, _Traits, _Alloc>::c_str [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>](), ((const std::allocator<char>&)((const std::allocator<char>*)(& std::allocator<char>())))))), globals-> FGGlobals::get_props(), globals-> FGGlobals::get_sim_time_sec(), 0u, 0u)'
/home/edi/games/fgfs/cvs/osg/OSG_OP_OT-1.2-Flightgear/OpenSceneGraph/include/osg/ref_ptr:32: note: candidates are: osg::ref_ptr<T>& osg::ref_ptr<T>::operator=(const osg::ref_ptr<T>&) [with T = osg::Node]
/home/edi/games/fgfs/cvs/osg/OSG_OP_OT-1.2-Flightgear/OpenSceneGraph/include/osg/ref_ptr:45: note:                 osg::ref_ptr<T>& osg::ref_ptr<T>::operator=(T*) [with T = osg::Node]
AIMgr.cxx:96: error: no match for 'operator=' in '((FGAIMgr*)this)->FGAIMgr::_defaultModel = sgLoad3DModel(((const std::string&)((const std::string*)globals-> FGGlobals::get_fg_root())), ((const std::string&)(& std::basic_string<char, std::char_traits<char>, std::allocator<char> >(planepath. std::basic_string<_CharT, _Traits, _Alloc>::c_str [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>](), ((const std::allocator<char>&)((const std::allocator<char>*)(& std::allocator<char>())))))), globals-> FGGlobals::get_props(), globals-> FGGlobals::get_sim_time_sec(), 0u, 0u)'
/home/edi/games/fgfs/cvs/osg/OSG_OP_OT-1.2-Flightgear/OpenSceneGraph/include/osg/ref_ptr:32: note: candidates are: osg::ref_ptr<T>& osg::ref_ptr<T>::operator=(const osg::ref_ptr<T>&) [with T = osg::Node]
/home/edi/games/fgfs/cvs/osg/OSG_OP_OT-1.2-Flightgear/OpenSceneGraph/include/osg/ref_ptr:45: note:                 osg::ref_ptr<T>& osg::ref_ptr<T>::operator=(T*) [with T = osg::Node]
AIMgr.cxx:104: error: no match for 'operator=' in '((FGAIMgr*)this)->FGAIMgr::_piperModel = sgLoad3DModel(((const std::string&)((const std::string*)globals-> FGGlobals::get_fg_root())), ((const std::string&)(& std::basic_string<char, std::char_traits<char>, std::allocator<char> >(planepath. std::basic_string<_CharT, _Traits, _Alloc>::c_str [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>](), ((const std::allocator<char>&)((const std::allocator<char>*)(& std::allocator<char>())))))), globals-> FGGlobals::get_props(), globals-> FGGlobals::get_sim_time_sec(), 0u, 0u)'
/home/edi/games/fgfs/cvs/osg/OSG_OP_OT-1.2-Flightgear/OpenSceneGraph/include/osg/ref_ptr:32: note: candidates are: osg::ref_ptr<T>& osg::ref_ptr<T>::operator=(const osg::ref_ptr<T>&) [with T = osg::Node]
/home/edi/games/fgfs/cvs/osg/OSG_OP_OT-1.2-Flightgear/OpenSceneGraph/include/osg/ref_ptr:45: note:                 osg::ref_ptr<T>& osg::ref_ptr<T>::operator=(T*) [with T = osg::Node]
make[2]: *** [ AIMgr.o] Error 1
make[2]: Leaving directory `/home/edi/games/simuladores/fgfs/cvs/osgflightgear/tmp/src/ATC'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/edi/games/simuladores/fgfs/cvs/osgflightgear/tmp/src'
make: *** [all-recursive] Error 1

I do not know C++ very much, so I do not understand what is the problem.

Please, help.
--
Woodyst.