MGv303 - Reweighting error

Dear experts,
I am trying to setup reweighting for the following setup. I am using the development branch MG v303-betternlops because of its exclusive ability to generate QCD NLO + Pythia8 PS samples with the UFO model SMEFTatNLO. I use the following commands:

import model SMEFTatNLO-NLO
generate p p > t t~ QCD=2 QED=0 NP=2
output test_dir
reweighting=ON
set nevents 100

The parameter card has all SMEFT parameters set to 0 except for the one I want to reweight in:

Block dim64f
20 1.000000e-02 # cQQ1

The reweighting card:

launch
      set dim64f 20 50.01

When passing these commands I get the following error:

Command "generate_events run_01" interrupted with error:
ImportError : No module named allmatrix2py
Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in '/nfs/scratch2/pverschu/3.0.3-betternlops/tt_SMEFT_LO_cQQ1_001_Reweight/run_01_tag_1_debug.log'.
Please attach this file to your report.

Let me know if this is sufficient information and how to resolve it.

Many thanks in advance.

Kind regards,

Pim