rake update error

rake production radiant:extensions:aggregation:update --trace
** Invoke production (first_time)
** Execute production
** Invoke environment (first_time)
** Execute environment
rake aborted!
Don't know how to build task 'radiant:extensions:aggregation:update'
/opt/ruby-enterprise-1.8.6-20081215/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:1704:in `[]'
/opt/ruby-enterprise-1.8.6-20081215/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:2026:in `invoke_task'
/opt/ruby-enterprise-1.8.6-20081215/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:2005:in `top_level'
/opt/ruby-enterprise-1.8.6-20081215/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:2005:in `each'
/opt/ruby-enterprise-1.8.6-20081215/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:2005:in `top_level'
/opt/ruby-enterprise-1.8.6-20081215/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:2044:in `standard_exception_handling'
/opt/ruby-enterprise-1.8.6-20081215/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:1999:in `top_level'
/opt/ruby-enterprise-1.8.6-20081215/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:1977:in `run'
/opt/ruby-enterprise-1.8.6-20081215/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:2044:in `standard_exception_handling'
/opt/ruby-enterprise-1.8.6-20081215/lib/ruby/gems/1.8/gems/rake-0.8.4/lib/rake.rb:1974:in `run'
/opt/ruby-enterprise-1.8.6-20081215/lib/ruby/gems/1.8/gems/rake-0.8.4/bin/rake:31
/opt/ruby-enterprise-1.8.6-20081215/bin/rake:19:in `load'
/opt/ruby-enterprise-1.8.6-20081215/bin/rake:19