Carrierwave Rails 3.1rc4 error

gistfile1.txt

NoMethodError in Podcasts#show

Showing /code/podcaster/app/views/podcasts/show.html.haml where line #13 raised:

You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.[]
Extracted source (around line #13):

10:   = @podcast.description
11: %p
12:   %b Image:
13:   = image_tag @podcast.image if @podcast.image
14: = link_to 'Edit', edit_podcast_path(@podcast)
15: |
16: = link_to 'Back', podcasts_path

actionpack (3.1.0.rc4) lib/sprockets/helpers/rails_helper.rb:87:in `rewrite_asset_path'
actionpack (3.1.0.rc4) lib/action_view/helpers/asset_paths.rb:23:in `compute_public_path'
actionpack (3.1.0.rc4) lib/sprockets/helpers/rails_helper.rb:76:in `compute_public_path'
actionpack (3.1.0.rc4) lib/action_view/helpers/asset_tag_helper.rb:277:in `image_path'
actionpack (3.1.0.rc4) lib/action_view/helpers/asset_tag_helper.rb:347:in `image_tag'
app/views/podcasts/show.html.haml:13:in `_app_views_podcasts_show_html_haml___3070217177827755239_2164156380'
actionpack (3.1.0.rc4) lib/action_view/template.rb:144:in `block in render'
activesupport (3.1.0.rc4) lib/active_support/notifications.rb:57:in `instrument'
actionpack (3.1.0.rc4) lib/action_view/template.rb:142:in `render'
actionpack (3.1.0.rc4) lib/action_view/renderer/template_renderer.rb:40:in `block (2 levels) in render_template'
actionpack (3.1.0.rc4) lib/action_view/renderer/abstract_renderer.rb:33:in `block in instrument'
activesupport (3.1.0.rc4) lib/active_support/notifications.rb:55:in `block in instrument'
activesupport (3.1.0.rc4) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (3.1.0.rc4) lib/active_support/notifications.rb:55:in `instrument'
actionpack (3.1.0.rc4) lib/action_view/renderer/abstract_renderer.rb:33:in `instrument'
actionpack (3.1.0.rc4) lib/action_view/renderer/template_renderer.rb:39:in `block in render_template'
actionpack (3.1.0.rc4) lib/action_view/renderer/template_renderer.rb:47:in `render_with_layout'
actionpack (3.1.0.rc4) lib/action_view/renderer/template_renderer.rb:38:in `render_template'
actionpack (3.1.0.rc4) lib/action_view/renderer/template_renderer.rb:12:in `block in render'
actionpack (3.1.0.rc4) lib/action_view/renderer/abstract_renderer.rb:22:in `wrap_formats'
actionpack (3.1.0.rc4) lib/action_view/renderer/template_renderer.rb:9:in `render'
actionpack (3.1.0.rc4) lib/action_view/renderer/renderer.rb:36:in `render_template'
actionpack (3.1.0.rc4) lib/action_view/renderer/renderer.rb:17:in `render'
actionpack (3.1.0.rc4) lib/abstract_controller/rendering.rb:120:in `_render_template'
actionpack (3.1.0.rc4) lib/action_controller/metal/streaming.rb:258:in `_render_template'
actionpack (3.1.0.rc4) lib/abstract_controller/rendering.rb:114:in `render_to_body'
actionpack (3.1.0.rc4) lib/action_controller/metal/renderers.rb:30:in `render_to_body'
actionpack (3.1.0.rc4) lib/action_controller/metal/compatibility.rb:43:in `render_to_body'
actionpack (3.1.0.rc4) lib/abstract_controller/rendering.rb:99:in `render'
actionpack (3.1.0.rc4) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (3.1.0.rc4) lib/action_controller/metal/instrumentation.rb:40:in `block (2 levels) in render'
activesupport (3.1.0.rc4) lib/active_support/core_ext/benchmark.rb:5:in `block in ms'
.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/benchmark.rb:309:in `realtime'
activesupport (3.1.0.rc4) lib/active_support/core_ext/benchmark.rb:5:in `ms'
actionpack (3.1.0.rc4) lib/action_controller/metal/instrumentation.rb:40:in `block in render'
actionpack (3.1.0.rc4) lib/action_controller/metal/instrumentation.rb:78:in `cleanup_view_runtime'
activerecord (3.1.0.rc4) lib/active_record/railties/controller_runtime.rb:24:in `cleanup_view_runtime'
actionpack (3.1.0.rc4) lib/action_controller/metal/instrumentation.rb:39:in `render'
actionpack (3.1.0.rc4) lib/action_controller/metal/implicit_render.rb:10:in `default_render'
actionpack (3.1.0.rc4) lib/action_controller/metal/mime_responds.rb:268:in `block in retrieve_response_from_mimes'
actionpack (3.1.0.rc4) lib/action_controller/metal/responder.rb:226:in `call'
actionpack (3.1.0.rc4) lib/action_controller/metal/responder.rb:226:in `default_render'
actionpack (3.1.0.rc4) lib/action_controller/metal/responder.rb:160:in `to_html'
responders (0.6.4) lib/responders/flash_responder.rb:93:in `to_html'
actionpack (3.1.0.rc4) lib/action_controller/metal/responder.rb:153:in `respond'
actionpack (3.1.0.rc4) lib/action_controller/metal/responder.rb:146:in `call'
actionpack (3.1.0.rc4) lib/action_controller/metal/mime_responds.rb:238:in `respond_with'
inherited_resources (1.2.2) lib/inherited_resources/actions.rb:13:in `show'
actionpack (3.1.0.rc4) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.1.0.rc4) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.1.0.rc4) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.1.0.rc4) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.1.0.rc4) lib/active_support/callbacks.rb:434:in `_run__264620615251303854__process_action__4457613619414557654__callbacks'
activesupport (3.1.0.rc4) lib/active_support/callbacks.rb:386:in `_run_process_action_callbacks'
activesupport (3.1.0.rc4) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.1.0.rc4) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.1.0.rc4) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.1.0.rc4) lib/active_support/notifications.rb:55:in `block in instrument'
activesupport (3.1.0.rc4) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (3.1.0.rc4) lib/active_support/notifications.rb:55:in `instrument'
actionpack (3.1.0.rc4) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.1.0.rc4) lib/action_controller/metal/params_wrapper.rb:202:in `process_action'
actionpack (3.1.0.rc4) lib/action_controller/metal/rescue.rb:17:in `process_action'
activerecord (3.1.0.rc4) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.1.0.rc4) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.1.0.rc4) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.1.0.rc4) lib/action_controller/metal.rb:193:in `dispatch'
actionpack (3.1.0.rc4) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.1.0.rc4) lib/action_controller/metal.rb:236:in `block in action'
actionpack (3.1.0.rc4) lib/action_dispatch/routing/route_set.rb:65:in `call'
actionpack (3.1.0.rc4) lib/action_dispatch/routing/route_set.rb:65:in `dispatch'
actionpack (3.1.0.rc4) lib/action_dispatch/routing/route_set.rb:29:in `call'
rack-mount (0.8.1) lib/rack/mount/route_set.rb:152:in `block in call'
rack-mount (0.8.1) lib/rack/mount/code_generation.rb:93:in `block in recognize'
rack-mount (0.8.1) lib/rack/mount/code_generation.rb:117:in `optimized_each'
rack-mount (0.8.1) lib/rack/mount/code_generation.rb:92:in `recognize'
rack-mount (0.8.1) lib/rack/mount/route_set.rb:141:in `call'
actionpack (3.1.0.rc4) lib/action_dispatch/routing/route_set.rb:531:in `call'
warden (1.0.4) lib/warden/manager.rb:35:in `block in call'
warden (1.0.4) lib/warden/manager.rb:34:in `catch'
warden (1.0.4) lib/warden/manager.rb:34:in `call'
actionpack (3.1.0.rc4) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.3.0) lib/rack/etag.rb:23:in `call'
rack (1.3.0) lib/rack/conditionalget.rb:25:in `call'
actionpack (3.1.0.rc4) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.1.0.rc4) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.1.0.rc4) lib/action_dispatch/middleware/flash.rb:243:in `call'
rack (1.3.0) lib/rack/session/abstract/id.rb:195:in `context'
rack (1.3.0) lib/rack/session/abstract/id.rb:190:in `call'
actionpack (3.1.0.rc4) lib/action_dispatch/middleware/cookies.rb:321:in `call'
activerecord (3.1.0.rc4) lib/active_record/query_cache.rb:54:in `call'
activerecord (3.1.0.rc4) lib/active_record/connection_adapters/abstract/connection_pool.rb:448:in `call'
actionpack (3.1.0.rc4) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (3.1.0.rc4) lib/active_support/callbacks.rb:392:in `_run_call_callbacks'
activesupport (3.1.0.rc4) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.1.0.rc4) lib/action_dispatch/middleware/callbacks.rb:28:in `call'
actionpack (3.1.0.rc4) lib/action_dispatch/middleware/reloader.rb:68:in `call'
rack (1.3.0) lib/rack/sendfile.rb:102:in `call'
actionpack (3.1.0.rc4) lib/action_dispatch/middleware/remote_ip.rb:48:in `call'
actionpack (3.1.0.rc4) lib/action_dispatch/middleware/show_exceptions.rb:47:in `call'
railties (3.1.0.rc4) lib/rails/rack/logger.rb:13:in `call'
rack (1.3.0) lib/rack/methodoverride.rb:24:in `call'
rack (1.3.0) lib/rack/runtime.rb:17:in `call'
activesupport (3.1.0.rc4) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.3.0) lib/rack/lock.rb:34:in `call'
actionpack (3.1.0.rc4) lib/action_dispatch/middleware/static.rb:53:in `call'
railties (3.1.0.rc4) lib/rails/engine.rb:438:in `call'
railties (3.1.0.rc4) lib/rails/railtie/configurable.rb:30:in `method_missing'