IM Installation V6.0.3-2 Failure to Set PAS Service Account
E.g. you could go to Control Panel>Administrative Tools>Services and attempt them there on the ABB Process Administration Service (=PAS)?
An error here indicate lack of permission (your login account) or something wrong with the 800xA Service Account you are trying to apply.
My second comment is, you must be logged into the IM node as either the Installer or Service account when executing this interface.
One last thing. There is a set of log files in the IM node that contain information about operations that are happening in the node. This is located in the directory, "C:\ProgramData\ABB\IM\History\log". There may be an indication as to the issue in one of these files.