taking the first of your 2 links from #1. book opens ok in sigil, but it crashes ADE 2.0 when i try to move past the 1st page
using sigil code view, I see that in 2nd file of book, the body section is empty... maybe that is the issue
<body>
<div class="body">
</div>
</body>
trying my own suggestion of calibre to calibre convert...
the converted version works in ADE
but... looking at the converted file in calibre editor. there is still an empty body section
<body class="calibre">
<div class="front">
</div>
</body>
...
its like I said before, the conversion fixes stuff faster than a manual debug.
others may be curious enough to dig deeper though
actually , this is more likely- running a check in calibre editor ( after the conversion) if gives 154 errors, nearly all to do with unsafe characters, e.g.
The filename OEBPS/@public@vhost@g@gutenberg@html@files@61324@61324-h@61324-h-11.htm_split_001.html contains unsafe characters, that must be escaped, like this OEBPS/%40public%40vhost%40g%40gutenberg%40html%40files%4 061324%4061324-h%4061324-h-11.htm_split_001.html. This can cause problems with some e-book readers. To be absolutely safe, use only the English alphabet [a-z], the numbers [0-9], underscores and hyphens in your file names. While many other characters are allowed, they may cause problems with some software.
i have no idea if there is a mechanism to report a problem book to PG