Bad integer for item 15 in list in ttbar+jj FxFx

Hi,

in ATLAS we are trying to develop a ttbar+up-to-2-jet FxFx setup.
A setup with one jet works but for two jets we get the following crash:

    Error termination. Backtrace:
    At line 410 of file reweight_xsec_events.f
    Fortran runtime error: Bad integer for item 15 in list input

As it takes significant CPU time to get to this part, we were wondering whether you have any pointers on how to debug this.

We set up the process with:

    import model loop_sm-no_b_mass
    define p = p b b~
    define j = p
    generate p p > t t~ [QCD] @0
    add process p p > t t~ j [QCD] @1
    add process p p > t t~ j j [QCD] @2

And make the following modifications to the default run card:

    'maxjetflavor' : 5,
    'parton_shower' : 'PYTHIA8',
    'dynamical_scale_choice' : '10', #user-defined scale -> Dominic's definition of mt+1/2*(pt^2+ptx^2)
    'ickkw' : 3,
    'jetradius' : 1.0,
    'ptj' : 10,
    'etaj' : 10

Cheers,
Hannes