Hmm, yes in the file classical.py before error line 199 you can find the developer comments:
def agg_dicts(self, acc, dic):
Aggregate dictionaries of hazard curves by updating the accumulator.
:param acc: accumulator dictionary
:param dic: dict with keys pmap, calc_times, rup_data
# NB: dic should be a dictionary, but when the calculation dies
# for an OOM it can become None, thus giving a very confusing error
if dic is None:
raise MemoryError('You ran out of memory!')
OOM meaning "out of memory" ... I would say 8GB RAM should be sufficient for this example, maybe if you look in the task manager, how much of that memory is free...?
Maybe there is some application that causes only fraction of the memory is available.
From the screenshots is seems more like OQ is running, just the amount of memory is not sufficient for some reason...