nfs-kernel-server not available

when configuring nfs-server via yast, ist says that the firewall can not be conigured because nfs-kernel-server is not available.
it is however installed.

how do I deal with that warning/error?

I have NFS working here.

That message is probably referring to a Yast component. It is true, that Yast does not configure the firewall for NFS. I had to do that separately.