PYTHIA 8 Error


I am trying to execute the example program based on Pythia8 $ROOTSYS/tutorials/pythia/pythia8.C
and i’m getting the following error:

PYTHIA Error: input string not found in settings databases::
SoftQCD:minBias = on
PYTHIA Abort from Pythia::init: some user settings did not make sense
PYTHIA Abort from Pythia::next: not properly initialized so cannot generate events

any guess? Thanks for the help