Hello,
There is a model used in your simulation that is not in the library. You will have to supply the model if you want other people to be able ot run your simulation.
You will get time step errors when the derivatives in the numerical solution become too large or unstable. What this means is that even with the smallest time step being used the derivatives can not be contained properly or change too rapidly.
A solution that works sometimes is to make the maximum step size smaller. This sometimes works because it allows the simulator algorithm to be able to control the derivatives leading up to the problem derivative(s) and thus when it gets there again it finds a naturally smoother solution and so is able to solve it with a reasonable time step.
This doesnt always work because sometimes the solution changes too fast (could be a 'shock') no matter what we do with the algorithm. The alternative is to find the problem time constant and try to slow it down a little without changing the overall simulation by too much. The odds are that slowing it down slightly wont change the overall results too much because the time frame over which the solution exists is typically very small compared to the larger time constants.