Ultimately I solved this error by updating to the latest version. My UiPath Studio did not auto-update, so I uninstalled and reinstalled the 2019.03 version, and used that same UiRobot version, as the online Orchestrator (Platform) is also showing as version 2019.03.
Anil_G
ashokkarale
jinal.shah
Gautham_Pattabiraman
postwick
chandreshsinh.jadeja
vrdabberu
Ajay_Mishra
sven.wullum1
Vyshnavi_Nalumachu