Cannot run urbackup server after installing on entware

Hello, I have installed urbackup-server successfully, but I cannot start/run it.
1.)
When I use:
S60urbackup-server start
I get:
Starting urbackupsrv… done.
but when I then check it by running:
S60urbackup-server check
I get:
Checking urbackupsrv… dead.
2.)
When I use:
urbackupsrv run
I get:
ERROR: Unable to change logfile ownership
ERROR: Cannot get uid and gid of user “urbackup” -1. Errno: 0
3.)
When I use:
urbackupsrv run -u root
I get:
Starting HTTP-Server on port 55414
HTTP: Server started up successfully!
SQLite: recovered 3 frames from WAL file /opt/var/urbackup/backup_server.db-wal code: 283
SQLite: recovered 3 frames from WAL file /opt/var/urbackup/backup_server.db-wal code: 283
LMDB: Failed to open LMDB database file (Operation not supported)
LMDB error creating env
Error creating file index
Setting up file index failed
Could not create or open file entry index. Exiting.

Any ideas, please?
Thank you,
Peter