in teach command, slider appears. but the plot figure window is empty-why?

in designing an RRPRR manipulator, i have used teach command. it gives no error. slider appears but the plot window is empty, can you tell me why??

i shall be really grateful for your help in this regard. here is my code:

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startup_rvc

l1=Link('d', 0, 'a', 0, 'alpha', 0, 'qlim', [0 180]);

l2=Link('d', 500, 'a', 0, 'alpha', -pi/2, 'qlim', [-90 90]);

l3=Link('theta', 0, 'a', 0, 'alpha', pi/2, 'qlim', [400 1100]);

l4=Link('d', 0, 'a', 0, 'alpha', 0, 'qlim', [0 180]);

l5=Link('d', 0, 'a', 0, 'alpha', -pi/2, 'qlim', [-90 90]);

myrobot=SerialLink([l1, l2, l3, l4, l5], 'name', 'robobolt');

%plot(myrobot,[1,1,1,1,1]);%gives an empty plot as well.......... :(

disp(robot)%properties displayed

robot.teach()

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thanks!!!!!!!!