Yes, I did. The errors happened all the same. I forgot to mention one thing: when I tried to edit the metadata and the error occurred after each character I typed, this only happened after I typed the first name and pressed the spacebar. That is, I could type the first name. However, if I copied and pasted the full text, the error also happened. Very strange. This was already happening before the settings were reset, it didn't change.
However, your suggestion still gave me an idea that should have been obvious, but somehow it didn't occur to me before. I decided to try something more radical and it worked: I thoroughly uninstalled and then reinstalled Calibre. I even used Revo Uninstaller Pro for a complete uninstall (it removed some leftover Registry entries, but it still missed the \AppData folders, which I manually deleted). Then I reinstalled Calibre and left it with the default settings. It imported the e-books normally. So, my problem is solved. Apparently, something in the Calibre install had been corrupted and that was fixed when I reinstalled it afresh.
Thanks a lot for your help, and also thanks for Calibre, which has become one of my favorite and indispensable pieces of software. You do a great job with it!
