Redmine

Hello, I upgraded Redmine from 1.0.x to 2.4.2.

All works fine, but after I migrate the DB, I get a "500 Internal Server Error" everytime I try to create or consult an issue.

This is the error in the log:
ActiveRecord::SubclassNotFound (The single-table inheritance mechanism failed to locate the subclass: 'WorkflowTransition'. This error is raised because the column 'type' is reserved for storing the class in case of inheritance. Please rename this column if you didn't intend it to be used for storing the inheritance class or overwrite Workflow.inheritance_column to use another column for that information.):
app/models/issue_status.rb:78:in `find_new_statuses_allowed_to'
app/models/issue.rb:467:in `new_statuses_allowed_to'
app/controllers/issues_controller.rb:117:in `show'
config/initializers/mongrel_cluster_with_rails_211_fix.rb:62:in `dispatch_cgi'

Rendering C:/Program Files/BitNami Redmine Stack/apps/redmine/public/500.html (500 Internal Server Error)

Database: Mysql

When i search for solution, they told copy the 3 work flow files. but those files are already there in my app/models folder.

Can any body have solution for this? Thanks in advance