what's the defalut password & the error" libzmq.so.4: cannot open shared "

ubgpu@ubgpu:~/github/DMLC/parameter_server/example/linear$ ../../script/ps.sh start ../../build/linear -app_file ctr/online_l1lr.conf
use binary [../../build/linear] and arg [-app_file ctr/online_l1lr.conf]
starting 1 servers and 1 workers
ubgpu@127.0.1.1's password:
ubgpu@127.0.1.1's password:
../../build/linear: error while loading shared libraries: libzmq.so.4: cannot open shared object file: No such file or directory
ubgpu@127.0.1.1's password:
ubgpu@127.0.1.1's password: ubgpu@127.0.1.1's password:
Permission denied, please try again.