unable to open .lit files

[Carl L Vancil, Jr.]

When I attempt to open a .lit file I get this error:

calibre, version 0.8.51
ERROR: Could not open ebook: I/O operation on closed file

Traceback (most recent call last):
  File "site-packages\calibre\gui2\viewer\main.py", line 38, in run
  File "threading.py", line 483, in run
  File "site-packages\calibre\ebooks\oeb\iterator\book.py", line 112, in __enter__
  File "site-packages\calibre\ebooks\oeb\iterator\book.py", line 44, in write_oebbook
  File "site-packages\calibre\ebooks\oeb\writer.py", line 64, in __call__
  File "site-packages\calibre\ebooks\oeb\base.py", line 954, in __str__
  File "site-packages\calibre\ebooks\oeb\base.py", line 909, in fget
  File "site-packages\calibre\ebooks\lit\reader.py", line 886, in read
  File "site-packages\calibre\ebooks\lit\reader.py", line 722, in get_file
  File "site-packages\calibre\ebooks\lit\reader.py", line 514, in read_content
  File "site-packages\calibre\ebooks\lit\reader.py", line 410, in wrapper
ValueError: I/O operation on closed file

I rolled back to Calibre 0.8.50 and now can open .lit files without any problem.

calibre Debug log
calibre 0.8.51
Windows-Vista-6.0.6002-SP2
Windows
('Windows', 'Vista', '6.0.6002')
Python 2.7.1
Windows: ('Vista', '6.0.6002', 'SP2', 'Multiprocessor Free')
Starting up...
Started up in 12.31 seconds with 4636 books
Worker Launch took: 0.206000089645