Program received signal SIGSEGV, Segmentation fault.
0x0804c250 in std::_Rb_tree<std::string, std::string, std::_Identity<std::string>, std::less<std::string>, std::allocator<std::string> >::_S_right (__x=0x80591) at stl_tree.h:501
501           { return static_cast<_Link_type>(__x->_M_right); }
(gdb) bt
#0  0x0804c250 in std::_Rb_tree<std::string, std::string, std::_Identity<std::string>, std::less<std::string>, std::allocator<std::string> >::_S_right (__x=0x80591) at stl_tree.h:501
#1  0x0804d685 in std::_Rb_tree<std::string, std::string, std::_Identity<std::string>, std::less<std::string>, std::allocator<std::string> >::_M_erase (this=0xbfa41ce4, __x=0x80591)
    at stl_tree.h:1264
#2  0x0804d694 in std::_Rb_tree<std::string, std::string, std::_Identity<std::string>, std::less<std::string>, std::allocator<std::string> >::_M_erase (this=0xbfa41ce4, __x=0x804af49)
    at stl_tree.h:1264
#3  0x0804d6e3 in ~_Rb_tree (this=0xbfa41ce4) at stl_tree.h:578
#4  0x0804d733 in ~set (this=0xbfa41ce4) at stl_set.h:108
#5  0x0804d8eb in ~variables_map (this=0xbfa41cc4) at variables_map.hpp:110
#6  0x0804ba41 in main (argc=-1208732280, argv=0x0) at main.cpp:57