Subversion 1.7 upgrade

I upgraded to Subversion 1.7. I installed the Subversion 1.7 command line client and TortoiseSVN 1.7. I successfully upgraded the working copy on several folders. On the last one, after doing the upgrade, it shows 2 modifications. In both cases when I diff the modified files, the base version was empty while the working copy had the correct file.

I tried the Update and then the Cleanup command but saw no changes. Then I tried to revert the files. When I attempted to revert, I got the following error. Does anyone have any suggestions for cleaning up my tree other than deleting it and doing a fresh checkout?

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Subversion Exception!
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Subversion encountered a serious problem.
Please take the time to report this on the Subversion mailing list
(users_at_subversion.apache.org)
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-1.7.0\ext\subversion\subversion\libsvn_wc\workqueue.c'
line 672: assertion failed (checksum != NULL)
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OK
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Received on 2011-10-18 07:29:03 CEST