No Problem, I have also changed some NFS settings on my NAS and will try out a few more things here. As I said, I have this problem with two different Kodi systems. Both systems differ in the case, but access the same DB and source. So the error must lie somewhere in this area.
I'll replace the Gbic on the NAS anyway, you never know...
I'm confused to the max myself because I've been using Kodi for a really long time and nothing has changed in the environment (before the error - apart from updates on the systems). If I find the error, I will of course let you know.