When someone is logged in as the db user, attempts to catalog any document, it throws an exception: Software error: Can't call method "get_effective_marcorgcode" on an undefined value at /home/l2c2technologies/kohaclone/cataloguing/value_builder/marc21_orgcode.pl line 31. While this is understandable, the error needs to be handled gracefully rather than expose the user to this error screen.
Almost everything will explode with the DB user, that's why there is a big warning on the main page. See bug 11590. *** This bug has been marked as a duplicate of bug 11590 ***
Also why we put the onboarding tool to allow a superlibrarian to be created at install time. You should probably never, ever, have a reason to log in as this user now.