Make sure you are logged into your mainframe and in USS (OMVS) using a 3270 emulator.

Make sure your ID has UID 0. To verify it, use the id command in USS:

> id

You should see something like:

> uid=0(<USERID>) gid=0(<GROUPID>)

Modify the permissions of the /tmp directory:

> chmod 1777 /tmp/

If you receive a file or directory not found message, enter the following commands to first create the directory and then modify the permissions:

> mkdir /tmp
> chmod 1777 /tmp/