I got an error, is this serious?

[x'shshui zh <x0...@gmail.com>]

---------------------------
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-1.7.5\ext\subversion\subversio
 n\libsvn_wc\wc_db.c'
 line 1597: assertion failed (SVN_IS_VALID_REVNUM(changed_rev))

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I just checkout some code from https://bitbucket.org/id804097/minnaedu.
On that page ,it is suggested that use "hg clone". then, I learned that
"svn checkout" may work, I try it on my windows 7.
what I surely curtain is that my network is really bad, when downloading
the
code it just reached 100+ bytes/sec.