PMDG_737ngx.dll error CTD

I recently experienced the PMDG_737ngx.dll error with a CTD when trying to load a saved flight. Fortunately, it has not repeated itself but in flying from EGPF to EDDB I did 4 saves and none of the four would load either from the free flight screen or the in-sim menu. Could I have done something to the panel that would have caused this? As I said, only these four instances but I want to avoid any future repeats. Any ideas?

halwatk