SimplaTable with error: singleton can't be dumped

Hello,

My first PDF report from rails.

When i try to render “tab.render_on(pdf)”, I get that error message.

Thanks any help,

Helder

=================================================================
TypeError in ContasController#plano

singleton can’t be dumped

RAILS_ROOT: script/…/config/…
Application Trace | Framework Trace | Full Trace

/var/lib/gems/1.8/gems/transaction-simple-1.4.0/lib/transaction/simple.rb:129:in
dump' /var/lib/gems/1.8/gems/transaction-simple-1.4.0/lib/transaction/simple.rb:129:instart_transaction’
/var/lib/gems/1.8/gems/transaction-simple-1.4.0/lib/transaction/simple/group.rb:102:in
start_transaction' /var/lib/gems/1.8/gems/transaction-simple-1.4.0/lib/transaction/simple/group.rb:102:ineach’
/var/lib/gems/1.8/gems/transaction-simple-1.4.0/lib/transaction/simple/group.rb:102:in
start_transaction' /var/lib/gems/1.8/gems/pdf-writer-1.1.3/lib/pdf/simpletable.rb:397:inrender_on’
app/controllers/contas_controller.rb:64:in plano' /var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/base.rb:1095:insend’
/var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/base.rb:1095:in
perform_action_without_filters' /var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:632:incall_filter’
/var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:634:in
call_filter' /var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:638:incall_filter’
/var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:438:in
call' /var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:637:incall_filter’
/var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:638:in
call_filter' /var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:438:incall’
/var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:637:in
call_filter' /var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:619:inperform_action_without_benchmark’
/var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/benchmarking.rb:66:in
perform_action_without_rescue' /var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/benchmarking.rb:66:inperform_action_without_rescue’
/var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/rescue.rb:83:in
perform_action' /var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/base.rb:430:insend’
/var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/base.rb:430:in
process_without_filters' /var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/filters.rb:624:inprocess_without_session_management_support’
/var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/session_management.rb:114:in
process' /var/lib/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/base.rb:330:inprocess’
/var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/rails.rb:78:in
process' /var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/rails.rb:76:insynchronize’
/var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/rails.rb:76:in
process' /var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:618:inprocess_client’
/var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:617:in each' /var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:617:inprocess_client’
/var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:736:in run' /var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:736:ininitialize’
/var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:736:in new' /var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:736:inrun’
/var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:720:in initialize' /var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:720:innew’
/var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel.rb:720:in run' /var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/configurator.rb:271:inrun’
/var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/configurator.rb:270:in
each' /var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/configurator.rb:270:inrun’
/var/lib/gems/1.8/gems/mongrel-1.0.1/bin/mongrel_rails:127:in run' /var/lib/gems/1.8/gems/mongrel-1.0.1/lib/mongrel/command.rb:211:inrun’
/var/lib/gems/1.8/gems/mongrel-1.0.1/bin/mongrel_rails:243
/var/lib/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:488:in
load' /var/lib/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:488:inload’
/var/lib/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:342:in
new_constants_in' /var/lib/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:488:inload’
/var/lib/gems/1.8/gems/rails-1.2.3/lib/commands/servers/mongrel.rb:60
/var/lib/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:495:in
require' /var/lib/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:342:innew_constants_in’
/var/lib/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:495:in
`require’
/var/lib/gems/1.8/gems/rails-1.2.3/lib/commands/server.rb:39