Liberate : error about "tcl command set" in lvf characterization

Hi, all:

    Recently I try to use liberate to characterize LVF for some stdcells in unified flow, but when I use “packet_mode cell" it will generate error:

  "Error - Tcl command set ::grid_bundle_dir exited with an error can't read "::grid_bundle_dir" : no such variable" when it start characterization bundle.

  I try to set that variable in char.tcl or use local host rather than distribution system, which can not fix that error. Therefore, I wanna ask some help for fixing this error.

  Liberate version: liberate/21.8.0

  packet command:

set packet_clients 100
set threads 2
set rsh_cmd "bsub -q ${bqueue} -R ‘span\[hosts=1\]’-n ${threads} -o %B/log -e %B/log"

set_var heartbeat_timeout 1200
set_var packet_clients ${packet clients}
set_var packet_client_log_timeout [expr { 1 * 3600 }]
set_var packet_client_timeout [expr { 3 * 3600 }]
set_var packet_client_timeout action "error"
set_var packet_client_resubmit count 5
set_var packet_log_filename "log
set_var packet_rsh_mode lsf
set_var bolt_optimize_client_submission 1

set_var packet_arc_job manager traditional
set_rsh_cmd $rsh_cmd $cells
set_var packet_mode "cell"

Thanks