Fatal error installing syslog-ng in Papertrail recipe

Here's the relevant output from the log:

/usr/local/ey_resin/ruby/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require': iconv will be deprecated in the future, use String#encode instead. ================================================================================

Error executing action `install` on resource 'package[app-admin/syslog-ng]'

================================================================================

Chef::Exceptions::Exec ---------------------- 

emerge -g --color n --nospinner --quiet =app-admin/syslog-ng-3.3.5 returned 1, expected 0 

Resource Declaration: --------------------- 

# In /etc/chef-custom/recipes/cookbooks/papertrail/recipes/default.rb 

42: package 'app-admin/syslog-ng' do 

43: version PAPERTRAIL_CONFIG[:syslog_ng_version] 

44: action :install 

45: end 

46: Compiled Resource: ------------------ 

# Declared in /etc/chef-custom/recipes/cookbooks/papertrail/recipes/default.rb:42:in `from_file' 

package("app-admin/syslog-ng") do 

  action [:install] 

  retries 0 

  retry_delay 2 

  package_name "app-admin/syslog-ng" 

  version "3.3.5" 

  cookbook_name :papertrail 

  recipe_name "default"

end 


...

[2013-06-15T07:56:13+00:00] INFO: Processing execute[get-latest-portage] action run (papertrail::default line 32) 

[2013-06-15T07:56:14+00:00] INFO: execute[get-latest-portage] ran successfully 

[2013-06-15T07:56:14+00:00] INFO: Processing file[unmasking app-admin/syslog-ng-3.3.5] action create (papertrail::default line 9) 

[2013-06-15T07:56:14+00:00] INFO: Processing ruby_block[append-to-/etc/portage/package.keywords/local] action create (papertrail::default line 28) 

[2013-06-15T07:56:14+00:00] INFO: Processing file[overriding hard mask for app-admin/syslog-ng-3.3.5] action create (papertrail::default line 9) 

[2013-06-15T07:56:14+00:00] INFO: Processing ruby_block[append-to-/etc/portage/package.unmask/engineyard_overrides] action create (papertrail::default line 28) [2013-06-15T07:56:14+00:00] INFO: Processing package[app-admin/syslog-ng] action install (papertrail::default line 42) 

[2013-06-15T07:56:16+00:00] ERROR: Running exception handlers [2013-06-15T07:56:16+00:00] ERROR: Exception handlers complete 

[2013-06-15T07:56:16+00:00] FATAL: Stacktrace dumped to /etc/chef-custom/recipes/chef-stacktrace.out 

[2013-06-15T07:56:16+00:00] FATAL: Chef::Exceptions::Exec: package[app-admin/syslog-ng] (papertrail::default line 42) had an error: Chef::Exceptions::Exec: emerge -g --color n --nospinner --quiet =app-admin/syslog-ng-3.3.5 returned 1, expected 0