Redmine

Dear all,

I am getting internal server error when I try to specify a due date to an existing issue. The stack trace is as follows. I suspect that something is wrong with my setup, because this is pretty basic functionality that probably works for everyone...

Processing IssuesController#update (for 77.111.90.94 at 2011-10-05 10:26:55) [PUT]
Parameters: {"time_entry"=>{"comments"=>"", "activity_id"=>"", "hours"=>""}, "commit"=>"Submit", "action"=>"update", "_method"=>"put", "authenticity_token"=>"PZ+7n9BQhB/JonL95CeHNewyYsvpuILK916OHBH4hXA=", "id"=>"870", "notes"=>"", "controller"=>"issues", "issue"=>{"start_date"=>"2011-09-11", "parent_issue_id"=>"", "estimated_hours"=>"16", "is_private"=>"0", "lock_version"=>"3", "priority_id"=>"4", "subject"=>"Alacsonyszintű programozás -- alapok", "fixed_version_id"=>"21", "category_id"=>"63", "description"=>"A hardware, fejelesztőkörnyezet és az API megismerése, tesztelése.", "tracker_id"=>"4", "done_ratio"=>"60", "due_date"=>"2011-10-14", "assigned_to_id"=>"28", "status_id"=>"2"}, "attachments"=>{"1"=>{"description"=>""}}}

TypeError (expected numeric or date):
/usr/lib/ruby/1.8/date.rb:1220:in `minus_without_duration'
app/models/issue.rb:606:in `save_issue_with_child_records'
app/models/issue.rb:588:in `save_issue_with_child_records'
app/controllers/issues_controller.rb:175:in `update'
config/initializers/mongrel.rb:62:in `dispatch_cgi'

Rendering /home/redmine/redmine-1.2.1/public/500.html (500 Internal Server Error)

tmahr@mass:/home/redmine/redmine$ RAILS_ENV=production script/about
About your application's environment
Ruby version 1.8.6 (x86_64-linux)
RubyGems version 1.4.2
Rack version 1.1.1
Rails version 2.3.11
Active Record version 2.3.11
Active Resource version 2.3.11
Action Mailer version 2.3.11
Active Support version 2.3.11
Edge Rails revision unknown
Application root /home/redmine/redmine-1.2.1
Environment production
Database adapter mysql
Database schema version 20110511000000

About your Redmine plugins
Redmine Version Burndown Charts plugin 0.0.5
Redmine Todo Lists plugin 0.0.3.7
Redmine Graphs plugin 0.1.0
Redmine Schedules plugin 0.4.2.1
Redmine Better Gantt Chart plugin 0.5.3
Timesheet Plugin 0.5.0
Redmine Attach Screenshot plugin 0.1.0
Redmine Theme Changer plugin 0.0.3
Redmine Work Time plugin 0.1.2
Mylyn Connector plugin 2.6.4.stable
Redmine Light Box plugin 0.0.1