WinCC OA - error when try to configure the ORACLE DB for RDB with way_of_backup set to datapump value

- OS Linux CentOS 7,
- WinCC OA v3.16 P019,
- Oracle client v.19c,
- Oracle Database 19c Enterprise Edition Release 19.0.0.0.0

If I run the unix_install.sh with way_of_backup set to datapump value I get the error (see the log attached).
If I change the way_of_backup to 'rman' the scipt is executed succefully.

What should I do to make the script work with way_of_backup set to datapump value (as recommended)?

Thank you.