The problem you are encountering in SIMULINK is specifically due to the integrator block, Kindly examine the initial conditions it should not lead to infinite or undefined states, you can also check on other blocks connected to the integrator block for initial conditions that might lead to a singularity or non-finite derivative.
You can also look for any equations or param's that could result in a division by zero or other operations that might lead to non-finite values. Additionaly try adjusting the solver settings.
Hope it helps!
Soumanth
