[economix]

Hi,
I get the following error converting a markdown formatted text file:

calibre, version 0.8.31
ERROR: Conversion Error: <b>Failed</b>: Convert book 1 of 1 (The Drive-In)

Convert book 1 of 1 (The Drive-In)
Resolved conversion options
calibre version: 0.8.31
{'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(., 'chapter|book|section|part\\s+', 'i')) or @class = 'chapter']",
 'chapter_mark': u'pagebreak',
 'comments': None,
 'cover': '/tmp/calibre_0.8.31_tmp_7viHRr/eWwJnr.jpeg',
 'debug_pipeline': None,
 'dehyphenate': True,
 'delete_blank_paragraphs': True,
 'disable_font_rescaling': False,
 'dont_split_on_page_breaks': False,
 'duplicate_links_in_toc': False,
 'enable_heuristics': False,
 'epub_flatten': False,
 'extra_css': u'h1 {text-align: center;}\nh2 {text-align: center; page-break-before: always;}\nh3 {text-align: center; page-break-before: always;}\nh4 {text-align: center;}\np {margin-top:0.2em; margin-bottom:0.2em; text-indent:1em; text-align:justify}\nh1+p, h2+p, h3+p, h4+p, p.whitespace+p, p.softbreak+p, hr+p {margin-top:0.2em; margin-bottom:0.2em; text-indent:0; text-align:justify}\nhr {width: 25%; height: 0px; border:0; colour: #FFFFFF; margin-top: 1em; margin-bottom: 1em;}\nh5 {page-break-before: always;}',
 'extract_to': None,
 'filter_css': u'',
 'fix_indents': True,
 'flow_size': 260,
 'font_size_mapping': None,
 'format_scene_breaks': True,
 'formatting_type': u'markdown',
 'html_unwrap_factor': 0.4,
 'input_encoding': None,
 'input_profile': <calibre.customize.profiles.KindleInput object at 0x253a710>,
 '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': u'//h:h2',
 'level2_toc': u'//h:h3',
 'level3_toc': None,
 'line_height': 0.0,
 'linearize_tables': False,
 'margin_bottom': 3.0,
 'margin_left': 3.0,
 'margin_right': 3.0,
 'margin_top': 3.0,
 'markdown_disable_toc': False,
 'markup_chapter_headings': True,
 'max_toc_links': 50,
 'minimum_line_height': 120.0,
 'no_chapters_in_toc': False,
 'no_default_epub_cover': True,
 'no_inline_navbars': False,
 'no_svg_cover': False,
 'output_profile': <calibre.customize.profiles.KindleOutput object at 0x253abd0>,
 'page_breaks_before': u'/',
 'paragraph_type': u'auto',
 'prefer_metadata_cover': False,
 'preserve_cover_aspect_ratio': False,
 'preserve_spaces': False,
 'pretty_print': True,
 'pubdate': None,
 'publisher': None,
 'rating': None,
 'read_metadata_from_opf': '/tmp/calibre_0.8.31_tmp_7viHRr/pnk24I.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'',
 'series': None,
 'series_index': None,
 'smarten_punctuation': False,
 'sr1_replace': None,
 'sr1_search': None,
 'sr2_replace': None,
 'sr2_search': None,
 'sr3_replace': None,
 'sr3_search': None,
 'tags': None,
 'timestamp': None,
 'title': None,
 'title_sort': None,
 'toc_filter': None,
 'toc_threshold': 6,
 'txt_in_remove_indents': False,
 'unsmarten_punctuation': False,
 'unwrap_lines': True,
 'use_auto_toc': False,
 'verbose': 2}
InputFormatPlugin: TXT Input running
on /tmp/calibre_0.8.31_tmp_7viHRr/Mh8IuM.txt
Reading text from file...
Detected input encoding as UTF-8 with a confidence of 100.0%
Auto detected paragraph type as single
Running text through markdown conversion...
Traceback (most recent call last):
  File "site.py", line 58, in main
  File "site-packages/calibre/utils/ipc/worker.py", line 187, in main
  File "site-packages/calibre/gui2/convert/gui_conversion.py", line 31, in gui_convert_override
  File "site-packages/calibre/gui2/convert/gui_conversion.py", line 25, in gui_convert
  File "site-packages/calibre/ebooks/conversion/plumber.py", line 959, in run
  File "site-packages/calibre/customize/conversion.py", line 204, in __call__
  File "site-packages/calibre/ebooks/txt/input.py", line 161, in convert
  File "site-packages/calibre/ebooks/txt/processor.py", line 106, in convert_markdown
  File "site-packages/calibre/ebooks/markdown/markdown.py", line 395, in convert
  File "site-packages/calibre/ebooks/markdown/extensions/toc.py", line 106, in run
IndexError: list index out of range

Any clues as to what would cause this errror?