Property 'upper_leg_length' is not recognized as valid

I have set a parameter for simulink matlab function ,when i run simulink it shows：

Property 'upper_leg_length' is not recognized as valid. Function 'forward_kinematics.m' (#154.69.90), line 2, column 8: "body.upper_leg_length"

i set body.upper_length=2.000

and here is my simulink matlab function :

 function end_e = forward(hr, hp, kp, body)
    ul=body.upper_leg_length;
    ll=body.lower_leg_length;
    end_e = [-ll*sin(kp+hp)-ul*sin(hp);
                     sin(hr)*(ll*cos(kp+hp)+ ul*cos(hp));
                     -cos(hr)*(ll*cos(kp+hp))+ ul*cos(hp)];
end

[Geoff Hayes]

Xinyi - you mention that you set body.upper_length=2.000. How is this related to the upper_leg_length? Are you assuming that the upper_leg_length should be automatically created? Or are these two variables the same and that your forward function should be

ul=body.upper_length;

instead? I don't know use Simulink so have not idea of what should be happening.