Parsing date from PayPal fails

I have a scenario where this code works on Ruby 1.8.6 on my local environment but my hosting provider uses Ruby 1.8.5, and it causes an exception.

The code in questions is:

dt = DateTime.parse(params[:payment_date])

and the date looks like: 09:45:21 Apr 30, 2007 PDT

Has anyone else run into this? Is there a prescribed way around it?

Exception follows:

ArgumentError (3 elements of civil date are necessary):     /usr/lib/ruby/1.8/date.rb:1214:in `new_with_hash'     /usr/lib/ruby/1.8/date.rb:1258:in `parse'     /app/controllers/ipn_controller.rb:12:in `paypal_ipn'     /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/ action_controller/base.rb:1095:in `send'     /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/ action_controller/base.rb:1095:in `perform_action_without_filters'     /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/ action_controller/filters.rb:632:in `call_filter'     /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/ action_controller/filters.rb:619:in `perform_action_without_benchmark'     /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/ action_controller/benchmarking.rb:66:in `perform_action_without_rescue'     /usr/lib/ruby/1.8/benchmark.rb:293:in `measure'     /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/ action_controller/benchmarking.rb:66:in `perform_action_without_rescue'     /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/ action_controller/rescue.rb:83:in `perform_action'     /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/ action_controller/base.rb:430:in `send'     /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/ action_controller/base.rb:430:in `process_without_filters'     /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/ action_controller/filters.rb:624:in `process_without_session_management_support'     /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/ action_controller/session_management.rb:114:in `process'     /usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/ action_controller/base.rb:330:in `process'     /usr/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/dispatcher.rb:41:in `dispatch'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/rails.rb: 78:in `process'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/rails.rb: 76:in `synchronize'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/rails.rb: 76:in `process'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:618:in `process_client'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:617:in `each'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:617:in `process_client'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:736:in `run'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:736:in `initialize'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:736:in `new'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:736:in `run'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:720:in `initialize'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:720:in `new'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:720:in `run'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/ configurator.rb:271:in `run'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/ configurator.rb:270:in `each'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/ configurator.rb:270:in `run'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/bin/mongrel_rails:127:in `run'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/command.rb: 211:in `run'     /usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/bin/mongrel_rails:243     /usr/bin/mongrel_rails:18:in `load'     /usr/bin/mongrel_rails:18