Rake abort 'const_missing' occurs if I have DATE_FORMATS set in environment.rb?

Hi,
I get the following error when I add a default DATE_FORMATS to my
environments.rb file? Any suggestions? The entry works fine, it’s
just
when I go to run “rake db:migrate:reset”.

------------addition to environment.rb--------------------------
ActiveSupport::CoreExtensions::Time::Conversions::DATE_FORMATS.merge!(
:default => ‘%d/%m/%Y’,
:date_time12 => “%d/%m/%Y %I:%M%p”,
:date_time24 => “%d/%m/%Y %H:%M”
)

------------ error -------------------------------------
Macintosh:myEquity greg$ rake db:migrate:reset --trace
(in /Volumes/USBOPEN/myEquity)
** Invoke db:migrate:reset (first_time)
** Invoke db:drop (first_time)
** Invoke environment (first_time)
** Execute environment
rake aborted!
uninitialized constant ActiveSupport
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:2237:in
const_missing' /Volumes/USBOPEN/myEquity/config/environment.rb:65 <=== POINTS TO THE LINE "ActiveSupport::CoreExtensions::Time::Conversions::DATE_FORMATS.merge!(" /opt/local/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/initializer.rb:47:inrun’
/Volumes/USBOPEN/myEquity/config/environment.rb:16
/opt/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
gem_original_require' /opt/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:inrequire’
/opt/local/lib/ruby/gems/1.8/gems/rails-2.0.2/lib/tasks/misc.rake:3
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:546:in call' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:546:inexecute’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:541:in each' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:541:inexecute’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:508:in
invoke_with_call_chain' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:501:insynchronize’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:501:in
invoke_with_call_chain' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:518:ininvoke_prerequisites’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1183:in each' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1183:insend’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1183:in each' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:515:ininvoke_prerequisites’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:507:in
invoke_with_call_chain' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:501:insynchronize’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:501:in
invoke_with_call_chain' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:518:ininvoke_prerequisites’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1183:in each' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1183:insend’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1183:in each' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:515:ininvoke_prerequisites’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:507:in
invoke_with_call_chain' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:501:insynchronize’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:501:in
invoke_with_call_chain' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:494:ininvoke’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1931:in
invoke_task' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1909:intop_level’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1909:in each' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1909:intop_level’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1948:in
standard_exception_handling' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1903:intop_level’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1881:in run' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1948:instandard_exception_handling’
/opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/lib/rake.rb:1878:in run' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.1/bin/rake:31 /opt/local/bin/rake:19:inload’
/opt/local/bin/rake:19

thanks