Access violation when calling some MFC default constructors

I am attempting to ask this question again due to m开发者_JAVA技巧y failure to state the question clearly yesterday. Basically, I have an access violation error described in the comment in the code below... any idea why?

Class A 
{
private:
    BOOL a;
    BOOL b;
    int i;
public:
    A() {a = FALSE; b = FALSE; i = 0;}
....
}


Class B : public A 
{
public:
    B() {} // empty constructor
....
}

Class C
{
public:
    C() {} // <-- when the constructor is calling the CButton and CCombobox 
           // default constructor for the member "cb" and "button", it overrides 
           // the address space of some of the variables defined in class A 
           // (e.g. a, and b would be changed to some garbage)
           // Basically, any variable defined below 'y' will have similar 
           // problems, though not exactly the same variables from 'y' will 
           // be changed..
private:
    int x;
    B y;
    CCombobox cb;
    CButton button;
}

• Check the call stack properly.
• Ensure object is allocated properly, try allocating it on stack (and not just by shortcut).
• Check the other classes do not have #pragma packing conflicts.
• Try removing some data-members from class C.

I've found the solution to my problem. The cause of the problem is that Class A is built to a dll with a different struct alignment than class B and C.