Can't convert any Book

[bobtorre]

Log included

Spoiler:

Convert book 1 of 1 (Il racconto dell'Ancella)
Conversion options changed from defaults:
cover: u'C:\\Users\\Roberto\\AppData\\Local\\Temp\\calibr e_3p_rfj\\gy_dll.jpeg'
read_metadata_from_opf: u'C:\\Users\\Roberto\\AppData\\Local\\Temp\\calibr e_3p_rfj\\sniwmz.opf'
verbose: 2
output_profile: u'kindle'
Resolved conversion options
calibre version: 3.47.1
{'asciiize': False,
'author_sort': None,
'authors': None,
'base_font_size': 0.0,
'book_producer': None,
'change_justification': u'original',
'chapter': u"//*[((name()='h1' or name()='h2') and re:test(., '\\s*((chapter|book|section|part)\\s+)|((prolog|pr ologue|epilogue)(\\s+|$))', 'i')) or @class = 'chapter']",
'chapter_mark': u'pagebreak',
'comments': None,
'cover': u'C:\\Users\\Roberto\\AppData\\Local\\Temp\\calibr e_3p_rfj\\gy_dll.jpeg',
'debug_pipeline': None,
'dehyphenate': True,
'delete_blank_paragraphs': True,
'disable_font_rescaling': False,
'dont_compress': False,
'duplicate_links_in_toc': False,
'embed_all_fonts': False,
'embed_font_family': None,
'enable_heuristics': False,
'expand_css': False,
'extra_css': None,
'extract_to': None,
'filter_css': u'',
'fix_indents': True,
'font_size_mapping': None,
'format_scene_breaks': True,
'html_unwrap_factor': 0.4,
'input_encoding': None,
'input_profile': <calibre.customize.profiles.InputProfile object at 0x055A4F70>,
'insert_blank_line': False,
'insert_blank_line_size': 0.5,
'insert_metadata': False,
'isbn': None,
'italicize_common_cases': True,
'keep_ligatures': False,
'language': None,
'level1_toc': None,
'level2_toc': None,
'level3_toc': None,
'line_height': 0.0,
'linearize_tables': False,
'margin_bottom': 5.0,
'margin_left': 5.0,
'margin_right': 5.0,
'margin_top': 5.0,
'markup_chapter_headings': True,
'max_toc_links': 50,
'minimum_line_height': 120.0,
'mobi_file_type': u'old',
'mobi_ignore_margins': False,
'mobi_keep_original_images': False,
'mobi_toc_at_start': False,
'no_chapters_in_toc': False,
'no_inline_navbars': True,
'no_inline_toc': False,
'output_profile': <calibre.customize.profiles.KindleOutput object at 0x055B12F0>,
'page_breaks_before': u'/',
'personal_doc': u'[PDOC]',
'prefer_author_sort': False,
'prefer_metadata_cover': False,
'pretty_print': False,
'pubdate': None,
'publisher': None,
'rating': None,
'read_metadata_from_opf': u'C:\\Users\\Roberto\\AppData\\Local\\Temp\\calibr e_3p_rfj\\sniwmz.opf',
'remove_fake_margins': True,
'remove_first_image': False,
'remove_paragraph_spacing': False,
'remove_paragraph_spacing_indent_size': 1.5,
'renumber_headings': True,
'replace_scene_breaks': u'',
'search_replace': '[]',
'series': None,
'series_index': None,
'share_not_sync': False,
'smarten_punctuation': False,
'sr1_replace': None,
'sr1_search': None,
'sr2_replace': None,
'sr2_search': None,
'sr3_replace': None,
'sr3_search': None,
'start_reading_at': None,
'subset_embedded_fonts': False,
'tags': None,
'timestamp': None,
'title': None,
'title_sort': None,
'toc_filter': None,
'toc_threshold': 6,
'toc_title': None,
'transform_css_rules': '[]',
'unsmarten_punctuation': False,
'unwrap_lines': True,
'use_auto_toc': False,
'verbose': 2}
InputFormatPlugin: EPUB Input running
on C:\Users\Roberto\AppData\Local\Temp\calibre_3p_rfj \a87x9u.epub
EPUB appears to be invalid ZIP file, trying a more forgiving ZIP parser
Traceback (most recent call last):
File "site-packages\calibre\ebooks\conversion\plugins\epub_in put.py", line 262, in convert
File "site-packages\calibre\utils\zipfile.py", line 766, in __init__
File "site-packages\calibre\utils\zipfile.py", line 801, in _GetContents
File "site-packages\calibre\utils\zipfile.py", line 816, in _RealGetContents
BadZipfile: File is not a zip file

Python function terminated unexpectedly
Not a ZIP file (Error Code: 1)
Traceback (most recent call last):
File "site.py", line 101, in main
File "site.py", line 78, in run_entry_point
File "site-packages\calibre\utils\ipc\worker.py", line 200, in main
File "site-packages\calibre\gui2\convert\gui_conversion.py", line 43, in gui_convert_override
File "site-packages\calibre\gui2\convert\gui_conversion.py", line 28, in gui_convert
File "site-packages\calibre\ebooks\conversion\plumber.py", line 1110, in run
File "site-packages\calibre\customize\conversion.py", line 246, in __call__
File "site-packages\calibre\ebooks\conversion\plugins\epub_in put.py", line 269, in convert
File "site-packages\calibre\utils\localunzip.py", line 232, in extractall
File "site-packages\calibre\utils\localunzip.py", line 219, in _extractall
ValueError: Not a ZIP file

[theducks]

The last line says it
someone has the wrong extension set on the file. It really was not a proper book file.
You might figure out what it was supposed to be with a Hex FILE editor