Redmine

Hello

we have the follow problem:
we create a subtask and from this subtask an other subtaks and now we will delete the last subtask.

Here we get this error:

Processing IssuesController#destroy (for 192.168.1.74 at 2011-12-02 07:26:20) [POST]
Parameters: {"action"=>"destroy", "authenticity_token"=>"gb8y8yR/PJzK1B0dKR8cjGBODdhp41LhswHZ50rKFpQ=", "id"=>"498", "controller"=>"issues"}

ArgumentError (comparison of Date with nil failed):
app/models/issue.rb:808:in `recalculate_attributes_for'
app/models/issue.rb:772:in `update_parent_attributes'
app/controllers/issues_controller.rb:246:in `destroy'
app/controllers/issues_controller.rb:244:in `each'
app/controllers/issues_controller.rb:244:in `destroy'
config/initializers/mongrel_cluster_with_rails_211_fix.rb:62:in `dispatch_cgi'

Rendering /opt/bitnami/apps/redmine/public/500.html (500 Internal Server Error)

Thx
Thomas

About your application's environment
Ruby version 1.8.7 (i686-linux)
RubyGems version 1.6.2
Rack version 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
Application root /opt/bitnami/apps/redmine
Environment production
Database adapter mysql
Database schema version 20110511000000

About your Redmine plugins
Mylyn Connector plugin 2.7.5.stable
Testlink Link plugin 0.7.1
Redmine Theme Changer plugin 0.0.3
Contacts plugin 2.2-light
Advanced roadmap & milestones plugin 0.5.1
Redmine Code Review plugin 0.4.4
Redmine Work Time plugin 0.1.4
Meetings plugin 0.0.1
Redmine Commit Relation Editor plugin 0.0.2
Redmine Hudson plugin 1.0.7
DMSF 1.2.2
Redmine Better Gantt Chart plugin 0.5.3
Issue Importer 0.9
Redmine Close Button plugin 0.0.6
Redmine Wiki Extensions plugin 0.3.6