Fortran runtime error, ValueError

Dear experts,

I'm trying to run the following process:
> generate n1 ~n1~ > zp

where n1 is a dark matter candidate and zp is a vector boson mediator. What I get is the following:

INFO: Checking for minimal orders which gives processes.
INFO: Please specify coupling orders to bypass this step.
INFO: Trying coupling order WEIGHTED<=2: WEIGTHED IS Zprm+MS0+2*QED+QCD
INFO: Trying process: n1 ~n1~ > g WEIGHTED<=2 @1
INFO: Trying process: n1 ~n1~ > a WEIGHTED<=2 @1
INFO: Trying process: n1 ~n1~ > z WEIGHTED<=2 @1
INFO: Process has 1 diagrams
INFO: Trying process: n1 ~n1~ > h WEIGHTED<=2 @1
INFO: Trying process: n1 ~n1~ > s0 WEIGHTED<=2 @1
INFO: Trying process: n1 ~n1~ > zp WEIGHTED<=2 @1
INFO: Process has 1 diagrams
2 processes with 2 diagrams generated in 0.023 s
Total: 2 processes with 2 diagrams
MG5_aMC>output
INFO: initialize a new directory: PROC_Z_DM_UFO_33
INFO: remove old information in PROC_Z_DM_UFO_33
INFO: Organizing processes into subprocess groups
INFO: Generating Helas calls for process: n1 ~n1~ > z WEIGHTED<=2 @1
INFO: Processing color information for process: n1 ~n1~ > z @1
INFO: Generating Helas calls for process: n1 ~n1~ > zp WEIGHTED<=2 @1
INFO: Processing color information for process: n1 ~n1~ > zp @1
INFO: Creating files in directory P1_n1xn1x_z
INFO: Generating Feynman diagrams for Process: n1 ~n1~ > z WEIGHTED<=2 @1
INFO: Finding symmetric diagrams for subprocess group n1xn1x_z
INFO: Creating files in directory P1_n1xn1x_zp
INFO: Generating Feynman diagrams for Process: n1 ~n1~ > zp WEIGHTED<=2 @1
INFO: Finding symmetric diagrams for subprocess group n1xn1x_zp
History written to /home/daniel/Documents/MG5_aMC_v2_4_2/PROC_Z_DM_UFO_33/Cards/proc_card_mg5.dat
Generated helas calls for 2 subprocesses (2 diagrams) in 0.004 s
Wrote files for 8 helas calls in 0.051 s
Export UFO model to MG4 format
ALOHA: aloha creates FFV1 routines
save configuration file to /home/daniel/Documents/MG5_aMC_v2_4_2/PROC_Z_DM_UFO_33/Cards/me5_configuration.txt
INFO: Use Fortran compiler gfortran
INFO: Use c++ compiler g++
INFO: Generate jpeg diagrams
INFO: Generate web pages
Output to directory /home/daniel/Documents/MG5_aMC_v2_4_2/PROC_Z_DM_UFO_33 done.
Type "launch" to generate events from this process, or see
/home/daniel/Documents/MG5_aMC_v2_4_2/PROC_Z_DM_UFO_33/README
Run "open index.html" to see more information about this process.
MG5_aMC>launch
************************************************************
* *
* W E L C O M E to *
* M A D G R A P H 5 _ a M C @ N L O *
* M A D E V E N T *
* *
* * * *
* * * * * *
* * * * * 5 * * * * *
* * * * * *
* * * *
* *
* VERSION 2.4.2 2016-06-10 *
* *
* The MadGraph5_aMC@NLO Development Team - Find us at *
* https://server06.fynu.ucl.ac.be/projects/madgraph *
* *
* Type 'help' for in-line help. *
* *
************************************************************
INFO: load configuration from /home/daniel/Documents/MG5_aMC_v2_4_2/PROC_Z_DM_UFO_33/Cards/me5_configuration.txt
INFO: load configuration from /home/daniel/Documents/MG5_aMC_v2_4_2/input/mg5_configuration.txt
INFO: load configuration from /home/daniel/Documents/MG5_aMC_v2_4_2/PROC_Z_DM_UFO_33/Cards/me5_configuration.txt
Using default text editor "vi". Set another one in ./input/mg5_configuration.txt
generate_events run_01
The following switches determine which programs are run:
 1 Run the pythia shower/hadronization: pythia=NOT INSTALLED
 2 Run PGS as detector simulator: pgs=NOT INSTALLED
 3 Run Delphes as detector simulator: delphes=NOT INSTALLED
 4 Decay particles with the MadSpin module: madspin=OFF
 5 Add weights to the events based on changing model parameters: reweight=OFF
  Either type the switch number (1 to 5) to change its default setting,
  or set any switch explicitly (e.g. type 'madspin=ON' at the prompt)
  Type '0', 'auto', 'done' or just press enter when you are done.
 [0, 4, 5, auto, done, madspin=ON, madspin=OFF, madspin, reweight=ON, ... ][60s to answer]
>0
Do you want to edit a card (press enter to bypass editing)?
  1 / param : param_card.dat
  2 / run : run_card.dat
  9 / plot : plot_card.dat
 you can also
   - enter the path to a valid card or banner.
   - use the 'set' command to modify a parameter directly.
     The set option works only for param_card and run_card.
     Type 'help set' for more information on this command.
   - call an external program (ASperGE/MadWidth/...).
     Type 'help' for the list of available command
 [0, done, 1, param, 2, run, 9, plot, enter path][60s to answer]
>0
Generating 10000 events with run name run_01
survey run_01
INFO: compile directory
compile Source Directory
Using random number seed offset = 21
INFO: Running Survey
Creating Jobs
Working on SubProcesses
INFO: P1_n1xn1x_z
INFO: P1_n1xn1x_zp
At line 199 of file ranmar.f
Fortran runtime error: Index '0' of dimension 1 of array 'ranu' below lower bound of 1

Error termination. Backtrace:
#0 0x7f2365fddf3a
#1 0x7f2365fdea95
#2 0x7f2365fdee67
#3 0x43617b
#4 0x41edcd
#5 0x4315e9
#6 0x403095
#7 0x40320a
#8 0x7f23656f882f
#9 0x401888
#10 0xffffffffffffffff
ERROR DETECTED
INFO: Idle: 1, Running: 0, Completed: 1 [ current time: 14h26 ]
INFO: Idle: 0, Running: 1, Completed: 1 [ current time: 14h26 ]
At line 199 of file ranmar.f
Fortran runtime error: Index '0' of dimension 1 of array 'ranu' below lower bound of 1

Error termination. Backtrace:
#0 0x7fa5fb8dcf3a
#1 0x7fa5fb8dda95
#2 0x7fa5fb8dde67
#3 0x43617d
#4 0x41edd3
#5 0x4315eb
#6 0x403095
#7 0x40320a
#8 0x7fa5faff782f
#9 0x401888
#10 0xffffffffffffffff
ERROR DETECTED
INFO: Idle: 0, Running: 0, Completed: 2 [ current time: 14h26 ]
INFO: End survey
refine 10000
Creating Jobs
INFO: Refine results to 10000
INFO: Generating 10000.0 unweigthed events.
Error when reading /home/daniel/Documents/MG5_aMC_v2_4_2/PROC_Z_DM_UFO_33/SubProcesses/P1_n1xn1x_z/G1/results.dat
Command "generate_events run_01" interrupted with error:
ValueError : need more than 5 values to unpack
Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in '/home/daniel/Documents/MG5_aMC_v2_4_2/PROC_Z_DM_UFO_33/run_01_tag_1_debug.log'.
Please attach this file to your report.
INFO:

INFO:

quit

The model works fine with other procesess like p p > Zp, p p > n1 ~n1~ and etc.

Thanks in advance for any hint!