pureftpd >> -lpuredb: error

Hi all, I’m trying to run pure-ftpd with virtual users by a puredb file: got this error:

/opt/sbin/pure-ftpd -j -lpuredb:/opt/etc/pureftpd.pdb &

421 Unknown authentication method: puredb:/opt/etc/pureftpd.pdb

[1] + Done (252) /opt/sbin/pure-ftpd -j -

When I use the -l unix switch everything is ok, any clues?

There may not be a db-auth included in QNX-Version

From the docu:
In its current form, Pure-FTPd uses some OS-specific system calls. And altough
some portability work has been done in order to ease its port to other
operating systems, only Linux FreeBSD, NetBSD, OpenBSD, ISOS, MirBSD, BSDi,
DragonflyBSD, Darwin, Solaris, Tru64, Irix, AIX and HPUX are known to work,
other operating systems may need some tweaks. With Linux, any modern
distribution should be ok.