Originally Posted by speakingtohe
I have never been able to view html(zip) files from within calibre but I have never had the zip internal viewer enabled before in preferences. Amazingly it seems to work.
Live and learn as they say.
For the other issues did you try adding books from directory, one book per directory?
Or opening main file with word and saving as rtf?
Both of these have worked for me for problem files but yours may be more problematic
Thanks, I did, it does not help.