Created Unassigned: execute impdp command [2590]

Hi I use runCommand to execute some basic ksh script without problems. (rm..).
But i can't run command with impdp.
var cmd = ssh.RunCommand("ssh oracle@192.168.1.31;cd /usr/oracle/app/admin/db01/dpdump/; impdp1.ksh>tata.txt"); I m able to run manually impdp1.ksh. I m run out of idea ? please any help
regards