e+e- > W+ W- b b~ not working at NLO

Dear madgraph experts,

I am trying to compute the cross-section of e+e- > W+ W- b b~ at NLO. What I do is the following:

generate e+ e- > W+ W- b b~ QED=4 QCD=0 [ all= QCD ] QCD=4
set complex_mass_scheme
output eewwbb
launch eewwbb

The launch takes place with the default parameters. However, this happens:

INFO: Starting run
INFO: Compiling the code
INFO: Lepton-Lepton collision: Ignoring 'pdlabel' and 'lhaid' in the run_card.
INFO: Compiling source...
INFO: ...done, continuing with P* directories
INFO: Compiling directories...
INFO: Compiling on 4 cores
INFO: Compiling P0_epem_wpwmbbx...

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
#0 0x7F4EB35CF777
#1 0x7F4EB35CFD7E
#2 0x7F4EB2ACFD3F
#3 0x4A9E27 in std::basic_stringbuf<char, std::char_traits<char>, std::allocator<char> >::~basic_stringbuf()
#4 0x4184F6
#5 0x419F14
#6 0x404D52
#7 0x40698C
#8 0x7F4EB2ABAEC4
#9 0x403D18
#10 0xFFFFFFFFFFFFFFFF

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
#0 0x7F4D9305E777
#1 0x7F4D9305ED7E
#2 0x7F4D9255ED3F
#3 0x4AA877 in std::basic_stringbuf<char, std::char_traits<char>, std::allocator<char> >::~basic_stringbuf()
#4 0x418F46
#5 0x41A964
#6 0x405683
#7 0x4073D8
#8 0x7F4D92549EC4
#9 0x403D18
#10 0xFFFFFFFFFFFFFFFF

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
#0 0x7FDE40B1A777
#1 0x7FDE40B1AD7E
#2 0x7FDE4001AD3F
#3 0xA67072 in std::basic_stringbuf<char, std::char_traits<char>, std::allocator<char> >::~basic_stringbuf()
#4 0x416116
#5 0x417B34
#6 0x482ABA in std::basic_stringbuf<char, std::char_traits<char>, std::allocator<char> >::~basic_stringbuf()
#7 0x48376A in std::basic_stringbuf<char, std::char_traits<char>, std::allocator<char> >::~basic_stringbuf()
#8 0x7FDE40005EC4
#9 0x404558
#10 0xFFFFFFFFFFFFFFFF

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
#0 0x7F997A5B4777
#1 0x7F997A5B4D7E
#2 0x7F9979AB4D3F
#3 0x4A5067 in std::basic_stringbuf<char, std::char_traits<char>, std::allocator<char> >::~basic_stringbuf()
#4 0x415926
#5 0x417344
#6 0x47CE46 in std::basic_stringbuf<char, std::char_traits<char>, std::allocator<char> >::~basic_stringbuf()
#7 0x47D553 in std::basic_stringbuf<char, std::char_traits<char>, std::allocator<char> >::~basic_stringbuf()
#8 0x7F9979A9FEC4
#9 0x403D68
#10 0xFFFFFFFFFFFFFFFF
INFO: P0_epem_wpwmbbx done.
INFO: Checking test output:
INFO: P0_epem_wpwmbbx
INFO: Result for test_ME:
INFO: Passed.
INFO: Result for test_MC:
INFO: Passed.
INFO: Result for check_poles:
WARNING: 0 points have been tried
INFO: Starting run
INFO: Using 4 cores
INFO: Cleaning previous results
INFO: Generating events without running the shower.
INFO: Setting up grid
INFO: Idle: 0, Running: 0, Completed: 0 [ current time: 14h11 ]
ls: cannot access P*/GF*: No such file or directory
ls: cannot access P*/GF*: No such file or directory
grep: P*/GF*/res_0: No such file or directory
Traceback (most recent call last):
  File "./sumres.py", line 131, in <module>
    (totABS, math.sqrt(errABS), math.sqrt(errABS)/totABS *100.,tot, math.sqrt(err), math.sqrt(err)/tot *100.)
ZeroDivisionError: float division by zero
INFO: Return code of the event collection: None
INFO: Output of the event collection:
N of directories: 0
Determining the number of unweighted events per channel
Found 0 correctly terminated jobs
Integrated abs(cross-section)
Integrated cross-section

Error detected in "launch auto "
write debug file /home/ferolo2/MadGraph/MG5_aMC_v2_3_0/bin/eewwbbNLO/run_07_tag_1_debug.log
If you need help with this issue please contact us on https://answers.launchpad.net/madgraph5
aMCatNLOError : An error occurred during the collection of results.
 Please check the .log files inside the directories which failed.
quit
INFO:

any idea?

Thank you a lot,
Fernando