In this article, we address the modeling and simulation of situated agents, together with the unreliability of their sensors and effectors. We propose a model for the simulation of the agent/environment interaction, that integrates uncertainties and errors of agent sensors and effectors. This model is built upon a stochastic modeling of the interaction. We illustrate an application of such a model in the case of simulating a set of mobile autonomous robots evolving in a structured environment (the inside of a building). Moreover, the built simulator has been designed to be executed on parallel computers and we describe its parallel implementation together with major results from a simulation point of view, as well as parallel performances.