C++ :: Boost Memory Mapped Object

i've created dll and implemented shared memory that every connected process can use. My problem is that i can't change anything in object, which is stored in the memory.

my class :

class MyClass
{
public:
MyClass();
void test();
int counter;
};
void MyClass::test() {
MessageBoxA(NULL, "test", "test", 0x0000000L);
counter++;
}

in stdafx.h i have :

static offset_ptr<MyClass> offset_mt;
static managed_shared_memory *memSegment;

I initialize shared memory and pointer :

memSegment = new managed_shared_memory(create_only, SHARED_MEMORY_NAME, 4096);
offset_mt = memSegment->construct<MyClass>("MyClass myClass")();

And then in an exported function i call

offset_mt.get()->test();

Im calling this from Java using JNA and result is a memory error (Invalid memory access). However, if I delete 'counter++' from test method, everything works fine - message box appears. Is there a limitation that I cant modify objects inside mapped memory or is this done the other way?