Memory error converting large mobi to epub

[ShellShock]

Hello Calibre gurus! Can anyone help with the following error, or am I stuffed? My input mobi is 20 MB, calibre-parallel.exe memory usage goes up to about 700MB before the error happens. I am using Windows 7 64 bit with 8GB RAM, approx 4 GB RAM free when the error happens. Thanks muchly. PS the Mobiunpack plug-in also fails with a memory error.

calibre, version 0.9.6 (win32, isfrozen: True)
Conversion Error: Failed

Convert book 1 of 1 
Resolved conversion options
calibre version: 0.9.6
{'asciiize': False,
 'author_sort': None,
 'authors': None,
 'base_font_size': 12.0,
 'book_producer': None,
 'change_justification': u'left',
 'chapter': u"//*[((name()='h1' or name()='h2') and re:test(., 'chapter|book|section|part\\s+', 'i')) or @class = 'chapter']",
 'chapter_mark': u'none',
 'comments': None,
 'cover': u'C:\\Users\\...\\AppData\\Local\\Temp\\calibre_0.9.6_tmp_8scm4z\\sdyvxi.jpeg',
 'debug_pipeline': None,
 'dehyphenate': True,
 'delete_blank_paragraphs': True,
 'disable_font_rescaling': True,
 'dont_split_on_page_breaks': False,
 'duplicate_links_in_toc': False,
 'embed_font_family': None,
 'enable_heuristics': False,
 'epub_flatten': False,
 'extra_css': None,
 'extract_to': None,
 'filter_css': u'',
 'fix_indents': True,
 'flow_size': 260,
 'font_size_mapping': u'7, 8, 10, 12, 14, 16, 18, 20',
 'format_scene_breaks': True,
 'html_unwrap_factor': 0.4,
 'input_encoding': None,
 'input_profile': <calibre.customize.profiles.KindleInput object at 0x046517F0>,
 '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': 0.0,
 'margin_left': 5.0,
 'margin_right': 5.0,
 'margin_top': 3.0,
 'markup_chapter_headings': True,
 'max_toc_links': 50,
 'minimum_line_height': 0.0,
 'no_chapters_in_toc': False,
 'no_default_epub_cover': True,
 'no_inline_navbars': False,
 'no_svg_cover': False,
 'output_profile': <calibre.customize.profiles.KoboReaderOutput object at 0x04651AF0>,
 'page_breaks_before': u"//*[name()='h1' or name()='h2']",
 'prefer_metadata_cover': False,
 'preserve_cover_aspect_ratio': True,
 'pretty_print': True,
 'pubdate': None,
 'publisher': None,
 'rating': None,
 'read_metadata_from_opf': u'C:\\Users\\...\\AppData\\Local\\Temp\\calibre_0.9.6_tmp_8scm4z\\m9f8ds.opf',
 'remove_fake_margins': True,
 'remove_first_image': False,
 'remove_paragraph_spacing': False,
 'remove_paragraph_spacing_indent_size': 1.0,
 'renumber_headings': True,
 'replace_scene_breaks': u'',
 'search_replace': '[]',
 '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,
 'start_reading_at': None,
 'subset_embedded_fonts': False,
 'tags': None,
 'timestamp': None,
 'title': None,
 'title_sort': None,
 'toc_filter': None,
 'toc_threshold': 6,
 'unsmarten_punctuation': False,
 'unwrap_lines': True,
 'use_auto_toc': False,
 'verbose': 2}
InputFormatPlugin: MOBI Input running
on C:\Users\...\AppData\Local\Temp\calibre_0.9.6_tmp_8scm4z\e3zglu.mobi
Extracting text...
Adding anchors...
Extracting text...
Adding anchors...
Python function terminated unexpectedly
   (Error Code: 1)
Traceback (most recent call last):
  File "site.py", line 132, in main
  File "site.py", line 109, in run_entry_point
  File "site-packages\calibre\utils\ipc\worker.py", line 186, 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 1009, in run
  File "site-packages\calibre\customize\conversion.py", line 239, in __call__
  File "site-packages\calibre\ebooks\conversion\plugins\mobi_input.py", line 34, in convert
  File "site-packages\calibre\ebooks\mobi\reader\mobi6.py", line 158, in extract_content
  File "encodings\cp1252.py", line 15, in decode
MemoryError

[ShellShock]

Not to worry, I have managed to unpack it using the mobi_unpack script.