500 error and tmp folder

Hi All,

I am periodically getting 500 errors from Mongrel when my app runs in
production mode. This corresponds to a repeated series of entries in the log
file that looks like this:

Permission denied - /tmp/ruby_sess.3d7c40b881a0124b
/usr/lib64/ruby/1.8/pstore.rb:289:in `initialize'
/usr/lib64/ruby/1.8/pstore.rb:289:in `transaction'
/usr/lib64/ruby/1.8/cgi/session/pstore.rb:71:in `initialize'
/usr/lib64/ruby/1.8/cgi/session.rb:273:in `initialize'
/usr/lib64/ruby/gems/1.8/gems/actionpack-1.12.5/lib/action_controller/cgi_process.rb:112:in
`session'
/usr/lib64/ruby/gems/1.8/gems/actionpack-1.12.5/lib/action_controller/cgi_process.rb:142:in
`stale_session_check!'
/usr/lib64/ruby/gems/1.8/gems/actionpack-1.12.5/lib/action_controller/cgi_process.rb:108:in
`session'
/usr/lib64/ruby/gems/1.8/gems/actionpack-1.12.5/lib/action_controller/base.rb:918:in
`assign_shortcuts_without_flash'
/usr/lib64/ruby/gems/1.8/gems/actionpack-1.12.5/lib/action_controller/flash.rb:141:in
`assign_shortcuts'
/usr/lib64/ruby/gems/1.8/gems/actionpack-1.12.5/lib/action_controller/base.rb:402:in
`process_without_filters'
/usr/lib64/ruby/gems/1.8/gems/actionpack-1.12.5/lib/action_controller/filters.rb:377:in
`process_without_session_management_support'
/usr/lib64/ruby/gems/1.8/gems/actionpack-1.12.5/lib/action_controller/session_management.rb:117:in
`process'
/usr/lib64/ruby/gems/1.8/gems/rails-1.1.6/lib/dispatcher.rb:38:in `dispatch'
/usr/lib64/ruby/gems/1.8/gems/mongrel-0.3.13.4/lib/mongrel/rails.rb:84:in
`process'
/usr/lib64/ruby/1.8/sync.rb:229:in `synchronize'
/usr/lib64/ruby/gems/1.8/gems/mongrel-0.3.13.4/lib/mongrel/rails.rb:83:in
`process'
/usr/lib64/ruby/gems/1.8/gems/mongrel-0.3.13.4/lib/mongrel.rb:580:in
`process_client'
/usr/lib64/ruby/gems/1.8/gems/mongrel-0.3.13.4/lib/mongrel.rb:579:in
`process_client'
/usr/lib64/ruby/gems/1.8/gems/mongrel-0.3.13.4/lib/mongrel.rb:686:in `run'
/usr/lib64/ruby/gems/1.8/gems/mongrel-0.3.13.4/lib/mongrel.rb:686:in `run'
/usr/lib64/ruby/gems/1.8/gems/mongrel-0.3.13.4/lib/mongrel.rb:673:in `run'
/usr/lib64/ruby/gems/1.8/gems/mongrel-0.3.13.4/lib/mongrel/configurator.rb:267:in
`run'
/usr/lib64/ruby/gems/1.8/gems/mongrel-0.3.13.4/lib/mongrel/configurator.rb:266:in
`run'
/usr/lib64/ruby/gems/1.8/gems/mongrel-0.3.13.4/bin/mongrel_rails:127:in `run'
/usr/lib64/ruby/gems/1.8/gems/mongrel-0.3.13.4/lib/mongrel/command.rb:211:in
`run'
/usr/lib64/ruby/gems/1.8/gems/mongrel-0.3.13.4/bin/mongrel_rails:231
/usr/bin/mongrel_rails:18

After a few minutes, I stop getting the error. Does anyone know what could be
causing this?

Thanks!
Daniel