This paper describes the new features implemented in WebSPN, a modeling tool for the analysis of non-Markovian stochastic Petri nets. WebSPN adopts a discretization of time and an approximation of non-exponentially distributed firing time transitions by means of the Phase type distribution. To improve the MPICH parallel implementation of this algorithm, in this paper we describe the porting of WebSPN from the MPI to the Grid computational paradigm. Besides a better flexibility in accessing computational and storage resources, one of the main advantages is the introduction of a Fault Recovery System to detect and recover from eventual machine faults. The resulting new tool is named Grid- SPN.