Error reported when running simulation

[CPU-beng]

In 'rov_simulation' Simulink, when I click the run button, it reports an error.
“Error evaluating 'InitFcn' callback for block_diagram 'ROV_Simulation'. Callback string is:

load('Simulation_busses.mat');
%Load simulator preferences
load("simparam.mat");

%Load Thruster settings
load("TAM.mat");
load("thrusterLimit.mat");

%Load External forces
load("External_forces.mat");

%Load Reference Case study
load("Reference_trajectory_case_study.mat");

if(not(isMATLABReleaseOlderThan("R2021b")))
set_param('ROV_Simulation/External Forces/Tether', 'commented', double(not(Sim_param.extTetUse)))
set_param('ROV_Simulation/External Forces/Manual disturbance', 'commented', double(not(Sim_param.extManUse)))
end

%Load sensors
load("Dependencies\Workspaces\Sensors.mat");
noise = NoiseSelection();

%Load Initial Conditions
load("InitCond.mat");
nu_Init = [nu_IC.u nu_IC.v nu_IC.w nu_IC.p nu_IC.q nu_IC.r];
eta_Init = [eta_IC.N eta_IC.E eta_IC.D eta_IC.phi eta_IC.theta eta_IC.psi];

% Load Physical parameters:
if(get_param('ROV_Simulation/Equation of Motion', 'use_app_parameters') == "on")
Env = LoadEnvironment(Sim_param.Env);
end

% Load robot chosen in "Equation of Motion" block:
if(get_param('ROV_Simulation/Equation of Motion', 'use_app_parameters') == "on")
Robot = LoadRobotParameters(Sim_param.Robot);
else
ROV_Constants;
Robot = ROV_Struct2Bus(ROV);
end

% Pos Rov
xi = eta_Init(1);
yi = eta_Init(2);
zi = eta_Init(3);

knots = 11;
len_tet = 35;
ln_tet = len_tet / (knots - 1);
z_tet_i = 0;
z1 = zi / 2 - ln_tet;

len_1 = len_tet / 2 - ln_tet;
x_tet = zeros(knots, 1);
z_tet = zeros(knots, 1);
if zi == len_tet
z_tet = linspace(0, zi, knots)';
else
x1 = sqrt(len_1^2 - z1^2);
a1 = (z1 - z_tet_i) / (x1 - 0);
x_inc = x1 / ((knots - 1) / 2 - 1);

for i=2:1:(knots - 1) / 2
    x_tet(i, 1) = x_inc * (i - 1);
end
z_tet(1:(knots - 1) / 2, 1) = a1 * x_tet(1:(knots - 1) / 2, 1);
z2 = zi / 2 + ln_tet;
x2 = sqrt(len_1^2 - z1^2);
a2 = (zi - z2) / (0 - x2);
x_tet((knots + 1) / 2:(knots - 1) / 2 + 2, 1) = x2;
z_tet((knots + 1) / 2) = z2 - ln_tet;
for i=(knots - 1) / 2 + 2:1:knots - 1
    x_tet(i + 1, 1) = x2 - x_inc * (i - ((knots + 1) / 2));
end
x_tet((knots - 1) / 2 + 1:(knots - 1) / 2 + 2, 1) = x2;
z_tet((knots + 1) / 2 + 1:end, 1) = a2 * x_tet((knots + 1) / 2 + 1:end, 1) + zi;

end
x_tet = x_tet + xi;
P10 = [xi yi zi]';
P9 = [x_tet(10) yi z_tet(10)]';
P8 = [x_tet(9) yi z_tet(9)]';
P7 = [x_tet(8) yi z_tet(8)]';
P6 = [x_tet(7) yi z_tet(7)]';
P5 = [(x_tet(6)) yi z_tet(6)]';
P4 = [x_tet(5) yi z_tet(5)]';
P3 = [x_tet(4) yi z_tet(4)]';
P2 = [x_tet(3) yi z_tet(3)]';
P1 = [x_tet(2) yi z_tet(2)]';
P0 = [xi yi 0]';
Reason: Cannot modify the contents of the Subsystem Reference block 'ROV_Simulation/External Forces' from within callbacks of the model 'ROV_Simulation'. To modify the contents, please use a self-modifying system encapsulation on the Subsystem Reference module.”