串行化继承CObject报错，求救。。。

class VexStruct : public CObject
{
public:
CPoint vertex;
int CountNum;

VexStruct(){} VexStruct(CPoint point,int i)
{
vertex=point;
CountNum=i;
} VexStruct& operator=(VexStruct &V)
{
vertex=V.vertex;
CountNum=V.CountNum;
return *this;
} //void Serialize(CArchive& ar)
//{//重载serialize函数
// CObject::Serialize(ar);
// if (ar.IsStoring())
// { // storing code
// ar<<vertex<<CountNum;
// }
// else
// { // loading code
// ar>>vertex>>CountNum;
// }
//} //DECLARE_SERIAL(VexStruct)};//IMPLEMENT_SERIAL(VexStruct,CObject,1)
报错这个：>f:\mfc\aoe\graphmfc\structs.h(43) : error C2248: “CObject::CObject”: 无法访问 private 成员(在“CObject”类中声明)
1>        c:\program files\microsoft visual studio 9.0\vc\atlmfc\include\afx.h(551) : 参见“CObject::CObject”的声明
1>        c:\program files\microsoft visual studio 9.0\vc\atlmfc\include\afx.h(522) : 参见“CObject”的声明怎么解决