Hello Alexey, thank you for the hint.
So, the paths are Ok as I said, also the file, which I found now, is OK and readable.
But the error persists.
There is still a point to check.
I had problems with file permissions in Windows since they still possess some permissions from the former win installation.
I tried to clean up the 'cadaver' permissions.
What I noticed, is that there were no permission for the 'normal' user (i.e. non admin) set. I suppose that this will also block PS when wanting to read files (images). Can this be?
I just changed this, but I'm not really aware about the user permission PS needs to operate smoothly.
Can someone give me some info on this?
Thanks