Fatal error given by Matlab GUI

I am getting this error after running my GUI [Fatal Error] :-1:-1: Premature end of file.

It happens during this block of code:

function figure1_WindowButtonMotionFcn(hObject, eventdata, handles)

% hObject handle to figure1 (see GCBO)

% eventdata reserved - to be defined in a future version of MATLAB

% handles structure with handles and user data (see GUIDATA)

pos = get(hObject,'CurrentPoint');

%CurrentPoint

posx = pos(1); posy = pos(2);

%Display to check to see if the position is working

posx = num2str(posx); posy = num2str(posy);

set(handles.Xpos,'String',posx); set(handles.Ypos,'String',posy);

%If mouse over then update the immage

 if ((115 < pos(1)) && (pos(1) < 125) && (7 < pos(2)) && (pos(2) < 11))
  axes(handles.axes1);
  imshow('condH.png')  
 else 
     axes(handles.axes1);
  imshow('cond.png')

 end

 if ((90 < pos(1)) && (pos(1) < 100) && (7 < pos(2)) && (pos(2) < 11))
  axes(handles.axes2);
  imshow('compH.png')  
 else
    axes(handles.axes2);
     imshow('comp.png')  
 end

 if ((80 < pos(1)) && (pos(1) < 90) && (7 < pos(2)) && (pos(2) < 11))
  axes(handles.axes3);
  imshow('evapH.png')  
 else
     axes(handles.axes3);
     imshow('evap.png')  
 end

 if ((90 < pos(1)) && (pos(1) < 100) && (2 < pos(2)) && (pos(2) < 5))
  axes(handles.axes4);
  imshow('expH.png')  
 else
     axes(handles.axes4);
     imshow('exp.png')  
 end

Normally the GUI runs fine until I trigger one of the if statements by mousing over the predetermined box. Then the GUI stops responding and will not open again until Matlab is restarted.