I think this may be a different bug? I have not had this in earier versions of Ubuntu, and this occurs with a newly installed Raring testing from today's daily build. The output on converting from lit and epub to mobi is as follows: calibre, version 0.9.0 (linux2, isfrozen: False) Conversion Error: Failed: Convert book 1 of 1 (The First Cut) Convert book 1 of 1 (The First Cut) Resolved conversion options calibre version: 0.9.0 {'asciiize': False, 'author_sort': None, 'authors': None, 'base_font_size': 0.0, 'book_producer': None, 'change_justification': u'justify', 'chapter': u"//*[((name()='h1' or name()='h2') and re:test(., '\\s*((chapter|book|section|part)\\s+)|((prolog|prologue|epilogue)(\\s+|$))', 'i')) or @class = 'chapter']", 'chapter_mark': u'pagebreak', 'comments': None, 'cover': u'/tmp/calibre_0.9.0_tmp_wFP7rZ/ZwF7xw.jpeg', 'debug_pipeline': None, 'dehyphenate': True, 'delete_blank_paragraphs': True, 'disable_font_rescaling': False, 'dont_compress': False, 'duplicate_links_in_toc': False, 'enable_heuristics': 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': , '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': , 'page_breaks_before': u"//*[name()='h1' or name()='h2']", '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'/tmp/calibre_0.9.0_tmp_wFP7rZ/6028O9.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, 'tags': None, 'timestamp': None, 'title': None, 'title_sort': None, 'toc_filter': None, 'toc_threshold': 6, 'toc_title': None, 'unsmarten_punctuation': False, 'unwrap_lines': True, 'use_auto_toc': False, 'verbose': 2} InputFormatPlugin: LRF Input running on /tmp/calibre_0.9.0_tmp_wFP7rZ/mQ9C9X.lrf Generating XML Converting XML to HTML... Parsing all content... Parsing 4.xhtml ... Forcing 4.xhtml into XHTML namespace Parsing 73.xhtml ... Forcing 73.xhtml into XHTML namespace Parsing 218.xhtml ... Forcing 218.xhtml into XHTML namespace Parsing 178.xhtml ... Forcing 178.xhtml into XHTML namespace Parsing 249.xhtml ... Forcing 249.xhtml into XHTML namespace Parsing 348.xhtml ... Forcing 348.xhtml into XHTML namespace Parsing 398.xhtml ... Forcing 398.xhtml into XHTML namespace Parsing 284.xhtml ... Forcing 284.xhtml into XHTML namespace Parsing 101.xhtml ... Forcing 101.xhtml into XHTML namespace Parsing 52.xhtml ... Forcing 52.xhtml into XHTML namespace Parsing 59.xhtml ... Forcing 59.xhtml into XHTML namespace Parsing 150.xhtml ... Forcing 150.xhtml into XHTML namespace Parsing 115.xhtml ... Forcing 115.xhtml into XHTML namespace Parsing 122.xhtml ... Forcing 122.xhtml into XHTML namespace Parsing 369.xhtml ... Forcing 369.xhtml into XHTML namespace Parsing 45.xhtml ... Forcing 45.xhtml into XHTML namespace Parsing 270.xhtml ... Forcing 270.xhtml into XHTML namespace Parsing 136.xhtml ... Forcing 136.xhtml into XHTML namespace Parsing 319.xhtml ... Forcing 319.xhtml into XHTML namespace Parsing 94.xhtml ... Forcing 94.xhtml into XHTML namespace Parsing 225.xhtml ... Forcing 225.xhtml into XHTML namespace Parsing 298.xhtml ... Forcing 298.xhtml into XHTML namespace Parsing 375.xhtml ... Forcing 375.xhtml into XHTML namespace Parsing 87.xhtml ... Forcing 87.xhtml into XHTML namespace Parsing 263.xhtml ... Forcing 263.xhtml into XHTML namespace Parsing 164.xhtml ... Forcing 164.xhtml into XHTML namespace Parsing 171.xhtml ... Forcing 171.xhtml into XHTML namespace Parsing 435.xhtml ... Forcing 435.xhtml into XHTML namespace Parsing 20.xhtml ... Forcing 20.xhtml into XHTML namespace Parsing 305.xhtml ... Forcing 305.xhtml into XHTML namespace Parsing 394.xhtml ... Forcing 394.xhtml into XHTML namespace Parsing styles.css ... Parsing 129.xhtml ... Forcing 129.xhtml into XHTML namespace Parsing 80.xhtml ... Forcing 80.xhtml into XHTML namespace Parsing 415.xhtml ... Forcing 415.xhtml into XHTML namespace Parsing 14.xhtml ... Forcing 14.xhtml into XHTML namespace Parsing 11.xhtml ... Forcing 11.xhtml into XHTML namespace Parsing 242.xhtml ... Forcing 242.xhtml into XHTML namespace Parsing 312.xhtml ... Forcing 312.xhtml into XHTML namespace Parsing 108.xhtml ... Forcing 108.xhtml into XHTML namespace Parsing 341.xhtml ... Forcing 341.xhtml into XHTML namespace Parsing 26.xhtml ... Forcing 26.xhtml into XHTML namespace Parsing 256.xhtml ... Forcing 256.xhtml into XHTML namespace Parsing 355.xhtml ... Forcing 355.xhtml into XHTML namespace Parsing 277.xhtml ... Forcing 277.xhtml into XHTML namespace Parsing 380.xhtml ... Forcing 380.xhtml into XHTML namespace Parsing 328.xhtml ... Forcing 328.xhtml into XHTML namespace Parsing 191.xhtml ... Forcing 191.xhtml into XHTML namespace Parsing 184.xhtml ... Forcing 184.xhtml into XHTML namespace Parsing 157.xhtml ... Forcing 157.xhtml into XHTML namespace Parsing 291.xhtml ... Forcing 291.xhtml into XHTML namespace Parsing 232.xhtml ... Forcing 232.xhtml into XHTML namespace Parsing 38.xhtml ... Forcing 38.xhtml into XHTML namespace Parsing 66.xhtml ... Forcing 66.xhtml into XHTML namespace Parsing 362.xhtml ... Forcing 362.xhtml into XHTML namespace Parsing 422.xhtml ... Forcing 422.xhtml into XHTML namespace Parsing 198.xhtml ... Forcing 198.xhtml into XHTML namespace Parsing 143.xhtml ... Forcing 143.xhtml into XHTML namespace Parsing 31.xhtml ... Forcing 31.xhtml into XHTML namespace Parsing 209.xhtml ... Forcing 209.xhtml into XHTML namespace Parsing 419.xhtml ... Forcing 419.xhtml into XHTML namespace Reading TOC from NCX... Merging user specified metadata... Detecting structure... Traceback (most recent call last): File "/usr/bin/calibre-parallel", line 20, in sys.exit(main()) File "/usr/lib/calibre/calibre/utils/ipc/worker.py", line 186, in main result = func(*args, **kwargs) File "/usr/lib/calibre/calibre/gui2/convert/gui_conversion.py", line 31, in gui_convert_override override_input_metadata=True) File "/usr/lib/calibre/calibre/gui2/convert/gui_conversion.py", line 25, in gui_convert plumber.run() File "/usr/lib/calibre/calibre/ebooks/conversion/plumber.py", line 1040, in run from calibre.ebooks.oeb.transforms.flatcss import CSSFlattener File "/usr/lib/calibre/calibre/ebooks/oeb/transforms/flatcss.py", line 19, in from calibre.ebooks.oeb.stylizer import Stylizer File "/usr/lib/calibre/calibre/ebooks/oeb/stylizer.py", line 23, in from lxml.cssselect import css_to_xpath, ExpressionError, SelectorSyntaxError File "/usr/lib/python2.7/dist-packages/lxml/cssselect.py", line 18, in raise ImportError('cssselect seems not to be installed. ' ImportError: cssselect seems not to be installed. See http://packages.python.org/cssselect/ Error in sys.excepthook: Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 111, in apport_excepthook if pr.check_ignored(): File "/usr/lib/python2.7/dist-packages/apport/report.py", line 945, in check_ignored dom = self._get_ignore_dom() File "/usr/lib/python2.7/dist-packages/apport/report.py", line 887, in _get_ignore_dom dom = xml.dom.getDOMImplementation().createDocument(None, 'apport', None) File "/usr/lib/python2.7/dist-packages/cssutils/__init__.py", line 166, in createDocument raise NotImplementedError NotImplementedError Original exception was: Traceback (most recent call last): File "/usr/bin/calibre-parallel", line 20, in sys.exit(main()) File "/usr/lib/calibre/calibre/utils/ipc/worker.py", line 186, in main result = func(*args, **kwargs) File "/usr/lib/calibre/calibre/gui2/convert/gui_conversion.py", line 31, in gui_convert_override override_input_metadata=True) File "/usr/lib/calibre/calibre/gui2/convert/gui_conversion.py", line 25, in gui_convert plumber.run() File "/usr/lib/calibre/calibre/ebooks/conversion/plumber.py", line 1040, in run from calibre.ebooks.oeb.transforms.flatcss import CSSFlattener File "/usr/lib/calibre/calibre/ebooks/oeb/transforms/flatcss.py", line 19, in from calibre.ebooks.oeb.stylizer import Stylizer File "/usr/lib/calibre/calibre/ebooks/oeb/stylizer.py", line 23, in from lxml.cssselect import css_to_xpath, ExpressionError, SelectorSyntaxError File "/usr/lib/python2.7/dist-packages/lxml/cssselect.py", line 18, in raise ImportError('cssselect seems not to be installed. ' ImportError: cssselect seems not to be installed. See http://packages.python.org/cssselect/