An administrator assigned the Organization Admin role is not able to create a new user with the amadmin command line utility due to incorrect logging privileges.
Workaround: Both the Organization Admin and the Top-level admin may set the permissions. To do so through the Administration Console:
Go to the organization to which the Organization Admin belongs.
Click on the Privileges tab.
Click on the Organization Admin Role link.
Select Read and write access to all log files or Write access to all log files.