Redmine

I've installed Redmine and linked it to a git repository that's been running development for a very long time (heavy, active development for about a year). Upon trying to load the Repository tab for the project I get an error. Here's the relevant section of the log:

Started GET "/redmine/projects/<project_name>/repository" for 173.164.56.105 at 2013-03-25 16:22:29 -0600
Processing by RepositoriesController#show as HTML
Parameters: {"id"=>"fredchat"}
Current user: admin (id=1)
Completed 500 Internal Server Error in 912ms

ActiveRecord::RecordNotUnique (Mysql2::Error: Duplicate entry '1-2a5b30caa8969dded7f57c9cda5f914ea88ea29f' for key 'changesets_repos_rev': INSERT INTO `changesets` (`comments`, `commit_date`, `committed_on`, `committer`, `repository_id`, `revision`, `scmid`, `user_id`) VALUES ('Merge branch \'autoupdate\' of <info_removed> into autoupdate', '2012-09-14 12:08:21', '2012-09-14 12:08:21', 'My Name <myemail@myemail.com>', 1, '2a5b30caa8969dded7f57c9cda5f914ea88ea29f', '2a5b30caa8969dded7f57c9cda5f914ea88ea29f', 4)):
app/models/repository/git.rb:222:in `save_revision'
app/models/repository/git.rb:211:in `block (2 levels) in save_revisions'
app/models/repository/git.rb:208:in `block in save_revisions'
app/models/repository/git.rb:207:in `each'
app/models/repository/git.rb:207:in `save_revisions'
app/models/repository/git.rb:154:in `fetch_changesets'
app/controllers/repositories_controller.rb:114:in `show'