The book is a Topaz book. This line gives it away:
Quote:
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Successfully Extracted Topaz contents
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Amazon has two different formats MOBI and TPZ. AZW being Amazon DRMed MOBI. TPZ is a very different file format and that plugin produces HTMLZ (it was originally created for calibre by me to allow for converting an EPUB to a single HTML file).
HTMLZ is a ZIP archive with a single HTML file inside of it. HTMLZ also has a few things like a metadata.opf file. As stated you can import the HTMLZ into calibre and convert to your preferred format.