Problem in GUI

[zulfiqarali37]

The GUI seems interesting and useful.
However, when we try to run the GUI and enter Fluid type the following error appears.

"Struct contents reference from a non-struct array object.

Error in Proyecto_transfer2>M_Tube_Callback (line 432)
contents = cellstr(get(handles.M_Tube,'String'));

Error in gui_mainfcn (line 95)
feval(varargin{:});

Error in Proyecto_transfer2 (line 42)
gui_mainfcn(gui_State, varargin{:});

Error in
matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)Proyecto_transfer2('M_Tube_Callback',hObject,eventdata,guidata(hObject))

Error while evaluating UIControl Callback"

Can you please guide where i am making error.

Thanks