Access denied for all users

I can do some debugging, but I'm not exactly sure what I need to do. What additional information do you need? I have found that it is specifically the revision view page that access is denied for. I can go to regular edit (node/%node/edit) or view (node/%node), but if I try to view a revision (node/%node/revisions/%rev/view) I get the access denied error in place of the form to edit the node. Are there other modules that are known to conflict with display suite?

Edit: this happens regardless of whether I actually have "revision" checked in node type-> manage display -> custom display settings. Also I am using book content type.

Ok, couple of updates. I have replicated this issue on a fresh subsite. Details below. From your tests I assume there is something different about my setup that is causing this issue. Even if my setup is incorrect for achieving my intended purpose, I still shouldn't be getting an access denied error, right? (Especially for admins) For the record, I was using page manager & views when I first encountered this issue, but not when I replicated it.

Replication procedure:

-Created new subsite (Drupal 7.7, released 2011-July-27)
-Installed modules display suite (7.x-1.x-dev), ctools (7.x-1.0-rc1), revisioning (7.x-1.2), enabled book content type
-Created roles & users, set role permissions
-Enabled revision view mode in Display Suite Extras
-Set book content type options for creating revisions (create new revision, new revision in draft, create new revision every time book content is updated)
-Created a book type node
-Went to revisions list for node (/node/%node/revisions)
-Clicked on the date for a revision row (/node/%node/revisions/%rev/view)
-Access denied message displayed instead of form
-Manually directing the browser to /node/%node/revisions/%rev/edit displays the regular revision edit form
-Disabling revision view mode in Display Suite Extras results in the regular revision view form, and re-enabling it results in the access denied message

I would like to solve this issue, because if my understanding of this module & overriding the revisioning display is correct, this functionality is exactly what I'm looking for. I need to override the view & edit display for book type, which includes the revisioning view and edit display, and this is the only module I've found that allows customizing the display of revisions. For the benefit of anyone in the future who stumbles upon this post looking for this functionality, here are some pages I've found containing relevant information:
http://drupal.org/node/1191336 - Issue discussion where Display Suite revision overrides are implemented
http://drupal.org/node/515518 - Issue discussion about overriding task handler for revisions. Results in the Revisioning module implementing the override, I assume for the option of whether links to edit or view revision content default to the current or latest revision (which doesn't allow display customization).
http://drupal.org/node/519924 - Issue discussion about integrating Panels and revisions. Remains unimplemented at the time of this posting.
http://drupal.org/node/1189928 - Issue posted by Panels user looking for the same functionality

The patch appears to resolve the access denied error. Thank you!! Looking at the patch, I thought it might make a difference if the Revisioning module was installed before or after the Display Suite module (with the patch), but the order of module installation doesn't appear to affect anything. I haven't tested the features of display suite with this patch, I just tested the error I encountered, but think if I run into issues with other features it would be unrelated. If you want to commit this patch that would be great. Thanks again!