Installing Nimsoft / Nimbus client worked for 2 out of 5 system. For the 2 that worked the robots showed up but the others do not.
Robot was running, telnetting from robot to hub and vice versa was fine.
CA UIM 7.6 or later
The problem was that the hub ip listed in the robot.cfg was incorrect.
Correcting the hub ip in the robot.cfg fixed the problem.