Basically, this indicates that all your substrates have been consumed, and your model is in equilibrium. How quickly that happens you can see when looking at the rate of your species. At the initial time you find them on the order of +/- 1e15 (consistent with 1/compartment size), so it will not be after 0.1 seconds that all substrates are consumed, but pretty much instantly. So you might want to look at:
* initial concentrations of your species
* parameter values of your reactions
* maybe change the unit of your compartment to something else than liter, so that you don't have a compartment size of 1e-15
best
Frank