How to add some user to some group in IBM BPM through DB

Sometimes you need to add some user to some group in BPM.
You can do this through admin console certainly.
But imagine that you have not any access to admin console.

DB2 SQL Error: SQLCODE=-1476, SQLSTATE=40506 during bootstrapProcesServerData in IBM IBM 8.5

During an installation of IBM BPM 8.5 on the step of bootstrapProcesServerData you can get roughly the message: