Generating some SM background

Hello,

I study a new particle having the following particles in its final state: " b b~ b b~ mu- mu+ vm~ vm",
so to see the background I generate " p p > b b~ b b~ mu- mu+ vm~ vm" in the SM. I think it's ok until now, but MadGraph gives the following error after launching the last process:

MadGraph5Error : A compilation Error occurs when trying to compile /home/safi/RECENT-9-14/MadGraph5_v1_5_12/del/SubProcesses/P0_gg_bbxbbxllvlvl.
 The compilation fails with the following output message:
     gfortran -O -w -ffixed-line-length-132 -w -c -o symmetry.o symmetry.f
     touch qmass.inc
     gfortran -O -w -ffixed-line-length-132 -w -c -o cuts.o cuts.f
     gfortran -O -w -ffixed-line-length-132 -w -c -o cluster.o cluster.f
     gfortran: internal compiler error: Killed (program f951)
     Please submit a full bug report,
     with preprocessed source if appropriate.
     See <file:///usr/share/doc/gcc-4.7/README.Bugs> for instructions.
     make: *** [symmetry.o] Error 4
     make: *** Waiting for unfinished jobs....

     f951: out of memory allocating 494521440 bytes after a total of 202997760 bytes
     make: *** [cluster.o] Error 1

 Please try to fix this compilations issue and retry.
 Help might be found at https://answers.launchpad.net/madgraph5.
 If you think that this is a bug, you can report this at https://bugs.launchpad.net/madgraph5

I'm using MadGraph5_v1_5_12, so what is the problem ?

Thanks,
S.S.