Memory allocation failed for SetupCtrl: ctrl->tpwgts

Hello,

I am trying to use ParMetis to partition the hexahedral mesh ~ 138 million into 16000 partitions (I have fortran program to read files, etc). I am getting following error. I am new to this and would appreciate if someone can help. Thanks much!
-----------------------------------------------------
in add_g_cv...
done add_g_cv...
in add_f_cv...
done add_f_cv...
in repartition, npart = 16000 ...
about to call METIS...
Current memory used: 240518168968 bytes
Maximum memory used: 240518168968 bytes
***Memory allocation failed for SetupCtrl: ctrl->tpwgts. Requested size: 4974156244448256 bytes
made it back from METIS. edgecut = 0
[ 0 ] Error: invalid part in ncv_ib.
[ 0 ] graceful_exit 0
*************** unused pparams *******************
************ end of unused pparams ***************