AfterEdit clear & add new items trouble

Hi

All I want to do is clear and add new items to de PropertyGrid after I select an option in one item... (I have a combobox with some options depending on the one you select, you will have different new options)

My class has this:
- "LoadInfo" method that clears all categories and then adds all items depending on the class info. (it uses beginUpdate and EndUpdate)
-  After edit function that changes some class atrributtes and returns a boolean which expresses whether the propertygrid needs to be reloaded or not.

In my AfterEditEventHandler:
void Form1::my_axPropertyGrid_AfterEdit(System::Object * sender, AxInterop::XtremePropertyGrid::_DPropertyGridEvents_AfterEdi tEvent * e){
    bool need_refresh = my_object->afteredit(sender,e);
    if (need_refresh){
        my_object->LoadInfo();
    }
}
And.... It crashes after doing the LoadInfo... I get a nice NullReferenceException ... Any Idea of what I´m doing wrong??