What causes error for referencing non-structure array in GUI ?

When I try to run my GUI I get this error, I've checked the tags but I don't know what could be causing it or what this error means?

Thanks in advanced

Attempt to reference field of non-structure array.

Error in tile_simulator>pushbutton1_CreateFcn (line 156)
axes(handles.axes1);

Error in gui_mainfcn (line 96)
        feval(varargin{:});

Error in tile_simulator (line 42)
    gui_mainfcn(gui_State, varargin{:});

Error in
@(hObject,eventdata)tile_simulator('pushbutton1_CreateFcn',hObject,eventdata,guidata(hObject))

Error using struct2handle
Error while evaluating uicontrol CreateFcn

Answer 1

[Walter Roberson]

I suspect that if you check, in that particular circumstance, handles is [] (empty)