Unable to update core. Error message says STATUS_ACCESS_VIOLATION

Hi,

I am unable to update drupal core to 6.20 using pm-update, and seem to get the following message:

Drush was unable to get the svn remote status on c:/Users/Robin/Documents/Work/Xyz/workspace/sitename/drupal-6.20. Check    ?[31;40m?[1
m[error]?[0m
that you have Subversion
installed, that this directory is a subversion working copy and that you have connectivity to the repository.
The specific errors are below:
      5 [main] svn 7380 exception::handle: Exception: STATUS_ACCESS_VIOLATION
   1583 [main] svn 7380 open_stackdumpfile: Dumping stack trace to svn.exe.stackdump

My setup is that the sites/ folder is an svn folder and then all Drupal core files and folders are not in source control.

My attempt at upgrading Drupal is to call drush pm-update --version-control=svn -v but this fails. From reading the error message I do not understand what steps I should take. Can someone point this out to me, or is this a drush bug?

Robin@Robin-M1330 /cygdrive/c/Users/Robin/Documents/Work/Xyz/workspace/sitename
$ svn st
 M      .
?       backup
?       sites/default/settings.php
M       sites/default/files/xmlsitemap/40cd750bba9870f18aada2478b24840a/1.xml

Robin@Robin-M1330 /cygdrive/c/Users/Robin/Documents/Work/Xyz/workspace/sitename
$ svn info
Path: .
URL: https://svn.mycompany.net/sitename/drupal-6/trunk
Repository Root: https://svn.mycompany.net
Repository UUID: e0457098-ff53-4530-a9f3-52e13ff9e479
Revision: 90
Node Kind: directory
Schedule: normal
Last Changed Author: robin
Last Changed Rev: 90
Last Changed Date: 2010-12-22 14:50:56 +0000 (Wed, 22 Dec 2010)


Robin@Robin-M1330 /cygdrive/c/Users/Robin/Documents/Work/Xyz/workspace/sitename
$ drush pm-update --version-control=svn -v
Initialized Drupal 6.19 root directory at c:/Users/Robin/Documents/Work/Xyz/workspace/sitename                                 [notice]

Initialized Drupal site default at sites/default                                                                                         [notice]

Refreshing update status information ...
WD update: Attempted to fetch information about all available new releases and updates.                                                  [notice]

Done.
Update information last refreshed: Wed, 12/22/2010 - 16:54

Update status information on all installed and enabled Drupal projects:
 Name                            Installed version  Proposed version  Status
 Administration menu             6.x-1.6            6.x-1.6           Up to date
 Admin role                      6.x-1.3            6.x-1.3           Up to date
 Advanced help                   6.x-1.2            6.x-1.2           Up to date
 Automatic Nodetitles            6.x-1.2            6.x-1.2           Up to date
 Drupal core                     6.19               6.20              Update available
 Content Construction Kit (CCK)  6.x-2.8            6.x-2.8           Up to date
 Devel                           6.x-1.23           6.x-1.23          Up to date
 Global Redirect                 6.x-1.3-alpha1     6.x-1.3-alpha1    Up to date
 GMap Module                     6.x-1.1            6.x-1.1           Up to date
 Link checker                    6.x-2.4            6.x-2.4           Up to date
 Page Title                      6.x-2.3            6.x-2.3           Up to date
 Pathauto                        6.x-1.5            6.x-1.5           Up to date
 Poormanscron                    6.x-2.2            6.x-2.2           Up to date
 Token                           6.x-1.15           6.x-1.15          Up to date
 Views                           6.x-2.12           6.x-2.12          Up to date
 Webform                         6.x-3.4            6.x-3.4           Up to date
 XML sitemap                     6.x-2.0-beta1      6.x-2.0-beta1     Up to date
 Zen                             6.x-2.0            6.x-2.0           Up to date
 Tao                             6.x-3.2            6.x-3.2           Up to date
 Rubik                           6.x-3.0-beta1      6.x-3.0-beta1     Up to date
 Austin Zen Sub Theme            6.x-2.x-dev        6.x-2.x-dev       Up to date


Code updates will be made to drupal core.
WARNING:  Updating core will discard any modifications made to Drupal core files, most noteworthy among these are .htaccess and robots.txt.  If y
ou have made any modifications to these files, please back them up before updating so that you can re-create your modifications in the updated ve
rsion of the file.
Note: Updating core can potentially break your site. It is NOT recommended to update production sites without prior testing.
Do you really want to continue? (y/n): y
Executing: svn info "c:/Users/Robin/Documents/Work/Xyz/workspace/sitename/drupal-6.20"                                         [notice]

Executing: cd c:/Users/Robin/Documents/Work/Xyz/workspace/sitename/drupal-6.20 && svn status  .htaccess .project               [notice]

CHANGELOG.txt COPYRIGHT.txt cron.php includes index.php INSTALL.mysql.txt INSTALL.pgsql.txt install.php INSTALL.txt LICENSE.txt
MAINTAINERS.txt misc modules profiles robots.txt scripts themes update.php UPGRADE.txt xmlrpc.php
Executing: cd c:/Users/Robin/Documents/Work/Xyz/workspace/sitename/drupal-6.20 && svn status -u  .htaccess .project            [notice]

CHANGELOG.txt COPYRIGHT.txt cron.php includes index.php INSTALL.mysql.txt INSTALL.pgsql.txt install.php INSTALL.txt LICENSE.txt
MAINTAINERS.txt misc modules profiles robots.txt scripts themes update.php UPGRADE.txt xmlrpc.php
Drush was unable to get the svn remote status on c:/Users/Robin/Documents/Work/Xyz/workspace/sitename/drupal-6.20. Check    ?[31;40m?[1
m[error]?[0m
that you have Subversion
installed, that this directory is a subversion working copy and that you have connectivity to the repository.
The specific errors are below:
      5 [main] svn 7380 exception::handle: Exception: STATUS_ACCESS_VIOLATION
   1583 [main] svn 7380 open_stackdumpfile: Dumping stack trace to svn.exe.stackdump
An error occurred at function : drush_pm_updatecode                                                                                   ?[31;40m?[1
m[error]?[0m
An error occurred at function : drush_pm_update                                                                                       ?[31;40m?[1
m[error]?[0m
Command dispatch complete                                                                                                                [notice]


Robin@Robin-M1330 /cygdrive/c/Users/Robin/Documents/Work/Xyz/workspace/sitename
$