Redmine

I got an issue with Related issues:
User with have the "manage_issue_relations" right don't see the options when working on a ticket. i see subtask and then nothing more where the related issues should appear, see http://imm.io/7RGB for a screen shot (in German).
nothing in production.log too.
As i have many plugins it could be related with one of them somehow.

Anybody got any ideas what's possible wrong?

PS:
It an old CentOS 5.5 and

$ RAILS_ENV=production script/about
About your application's environment
Ruby version 1.8.7 (x86_64-linux)
RubyGems version 1.6.2
Rack version 1.1.2
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 /home/prod/redmine
Environment production
Database adapter mysql
Database schema version 20110511000000

About your Redmine plugins
Timesheet Plugin 0.6.0
Redmine Graphs plugin 0.1.0
Redmine Wiki Unc plugin 0.0.2
Redmine Wiki Issue Details plugin 0.1.0
Redmine Context Menu Relations plugin 0.0.1
Redmine Gist embed plugin 0.1.0
Redmine Time Tracker plugin 0.4
Stuff To Do Plugin 0.4.0
Redmine Closed Date plugin 0.0.1
Redmine Backlogs master branch (unstable)
Projects Tree View plugin 0.0.2
Redmine Wiki Extensions plugin 0.2.2
Redmine Newissuealerts plugin 0.0.2
Bulk Time Entry 0.5.0
Issues XLS export 0.1.3
Redmine Charts 0.1.0
Redmine OpenID Selector plugin 0.0.1
Redmine Ultraviolet Syntax highlighting plugin 0.0.3
redmine_tags 1.1.4
Redmine Codebook plugin 0.3.1
Redmine Schedules plugin 0.4.2
Redmine Reports plugin 0.1.0
Issue Due Date 0.1.0
Mylyn Connector plugin 2.7.2.stable