Cannot add task in the Dashboard

[olylakers]

When clicking on the Add task in the Dashboard,the new task div will be poped up but a endless circle is display in this page.

The server log is :

Processing IssueSprintsController#new (for 127.0.0.1 at 2011-05-03 13:04:57) [GET]
Parameters: {"user_story_id"=>"3", "project_id"=>"minise", "action"=>"new", "controller"=>"issue_sprints"}

NoMethodError (undefined method user_story_id=' for nil:NilClass): vendor/plugins/redmine_sprints/app/controllers/issue_sprints_controller.rb:11:innew'
d:/Ruby187/lib/ruby/1.8/webrick/httpserver.rb:104:in service' d:/Ruby187/lib/ruby/1.8/webrick/httpserver.rb:65:inrun'
d:/Ruby187/lib/ruby/1.8/webrick/server.rb:173:in start_thread' d:/Ruby187/lib/ruby/1.8/webrick/server.rb:162:instart'
d:/Ruby187/lib/ruby/1.8/webrick/server.rb:162:in start_thread' d:/Ruby187/lib/ruby/1.8/webrick/server.rb:95:instart'
d:/Ruby187/lib/ruby/1.8/webrick/server.rb:92:in each' d:/Ruby187/lib/ruby/1.8/webrick/server.rb:92:instart'
d:/Ruby187/lib/ruby/1.8/webrick/server.rb:23:in start' d:/Ruby187/lib/ruby/1.8/webrick/server.rb:82:instart'

Rendering rescues/layout (internal_server_error)

Can you please help me resolve this issue? Thanks