Cannot open and run simulink because 'spec1' does not exist

I am unable to run 'LeadVehicle' because 'spec1' cannot be found.

1. I have no idea what 'spec1' is. I never created it.
2. I followed the 'Open Models' instructions. I loaded "mpc1_1.mat" and then opened Simulink: 'LeadVehicle'.
3. The MPC Designer (LeadVehicle/MPC) (bottom panel) is correct. It appears that it loaded the "mpc1_1.mat" data correctly.

MATLAB Version: 23.2.0.2391609 (R2023b) Update 2

[Paul Ossenbruggen]

4. The ErrorAfterTestung.pdf shows that I am able to run parts of Simulink successfully. Tuning works as shown.

5. Update and Simulate gives " 'spec1' cannot be found. "

It is a mystery where spec1 comes from.

[Walter Roberson]

It is used in the configuration parameters dialog for block LeadVehicle.

[Paul Ossenbruggen]

Since I got nowhere with 'spec1', I started from scratch and did not produce the error.

Thanks