app calling dll crashes

attached zip file is part of an online code. it is used to create a dll for another exe app. copied its .dll and .lib to another project (mfc exe). crashes toward the end. can't figure why this crashes.

code to call the dll:
typedef int (CALLBACK* FirstFunction)();
typedef int (CALLBACK* SecondFunction)(int&, int&);

void CMyDlg::OnBnClickedButton1()
{
HINSTANCE hClcltr=LoadLibrary("dlltest.dll");
FirstFunction LPFF;
LPFF = (FirstFunction)GetProcAddress(hClcltr,"firstgo");

SecondFunction LPSF;
LPSF = (SecondFunction)GetProcAddress(hClcltr,"go");

int i;
int j;
LPFF();
LPSF(i,j);
}

Have you run it in the debugger?

Sorry. My browser was too slow that i did not think the first try went through. i am in remote village. anyway, this is error that i get when i run it in debugger:
Unhandled exception at 0x00000000 in callYdll.exe: 0xC0000005:
Access violation reading location 0x00000000.

that was what i did. i started it with debugging option. i got Unhandled exception at 0x00000000 ,,, . not sure what causes it.

it crashes at the first exported function. can someone take a look at the attached code?. not fully familiar with debugging the dll process.

thanks. yes i knew it this way. i repeated the same steps. it crashes at the
second function. not sure why?.
dll code:
void CGClass::firstgo()
{
s = new Cderivedclass (2);
}
void CGClass::go(int& i, int& j)
{
s->push (1); <<-- based on debugger it crashes here.
s->push (2);

i = s->pop();
j = s->pop();
}
Unhandled exception at 0x00316dbb in callYdll.exe: 0xC0000005:
Access violation writing location 0x77fbb286.

not sure what type of memory access viloation is taking place.

this works but could someone check for any error?.

CIIFoo is inherited from CIFoo.
dll returns a class:
void* CGClass::ReturnCIIFooInstance()
{
return static_cast< void* > (new CIIFoo);
}
---
//CIFoo is base class (abstract class).
int _tmain(int argc, _TCHAR* argv[])
{
HINSTANCE hdll = NULL;
CIFoo* FooPtr = NULL;
typedef void* (CALLBACK *pFuncP)();
pFuncP MyFoo;

hdll = LoadLibrary("dllt.dll");
MyFoo = (pFuncP)GetProcAddress( hdll, "ReturnCIIFooInstance" );

FooPtr = static_cast<CIFoo*>(MyFoo());

int i = 8;
FooPtr->SetNumber(i);
std::cout << "Foo::number is : " << FooPtr-> GetNumber() << std::endl;

delete FooPtr;
FooPtr = NULL;
FreeLibrary(hdll);
return 0;
}
couldn't fix the attached.