assertion failed (status != svn_wc__db_status_normal)

I get the following error when trying to update a checkout. I did a
cleanup of the checkout, but that did not affect the error. The problem
occurs only with one specific checkout, and on re-downloading out the
same repository I do not get the error on the new checkout. I am using
TortoiseSVN on Windows 7, 64 bit.

---------------------------
Subversion Exception!
---------------------------
Subversion encountered a serious problem.
Please take the time to report this on the Subversion mailing list
with as much information as possible about what
you were trying to do.
But please first search the mailing list archives for the error message
to avoid reporting the same problem repeatedly.
You can find the mailing list archives at
http://subversion.apache.org/mailing-lists.html

Subversion reported the following
(you can copy the content of this dialog
to the clipboard using Ctrl-C):

In file
  'D:\Development\SVN\Releases\TortoiseSVN-1.7.8\ext\subversion\subversion\libsvn_wc\update_editor.c'
  line 2899: assertion failed (status != svn_wc__db_status_normal)

TortoiseSVN 1.7.8, Build 23174 - 64 Bit , 2012/08/13 19:49:45
Subversion 1.7.6,
apr 1.4.6
apr-utils 1.3.12
neon 0.29.6
OpenSSL 1.0.1c 10 May 2012
zlib 1.2.7

-- 
Peter Amstutz
Senior Software Engineer
Technology Solutions Experts
Natick, MA
02131