How can I load a name file that i received from a guide list box ?

I tried this way:

_global data;
vars = evalin('base','who');
set(handles.data_files,'String',vars);
contents = get(hObject,'String');
data=contents{get(hObject,'Value')};

---//---

global data;
global eeg_matrix;
eeg_matrix=load(data);_

And the error returned was:

??? Error using ==> load
Unable to read file eeg6_crise: No such file or directory.

Error in ==> load_data>done_Callback at 109
eeg_matrix=load(data);

Error in ==> gui_mainfcn at 96
      feval(varargin{:});

Error in ==> load_data at 42
  gui_mainfcn(gui_State, varargin{:});

Error in ==>
@(hObject,eventdata)load_data('done_Callback',hObject,eventdata,guidata(hObject))

??? Error while evaluating uicontrol Callback