Redmine

Envirement:
Redmine2.1.4
Apache2
Passenger

I have installed the redmine with the envirement upon.
But when I wanted to add a attachement:a.txt,error occured.
The page shows:
-----------------------
Internal error
An error occurred on the page you were trying to access.
If you continue to experience problems please contact your Redmine administrator for assistance.

If you are the Redmine administrator, check your log files for details about the error.
-----------------------

I checked the logs: var/apache2/error.log
Log shows:

WARNING:Can't verify CSRF token authenticity.

Errorno::EACCESS (Permission denied - /usr/local/share/redmine-2.1.4/files/121222140101_a.txt):
app/models/attachment.rb:107:in 'initalize'
app/models/attachment.rb:107:in 'open'
app/models/attachment.rb:107:in 'file_to_final_location'
lib/plugin/acts_as_attachment/lib/acts_as_attachable.rb:84:in 'block in save_attachments'
lib/plugin/acts_as_attachment/lib/acts_as_attachable.rb:80:in 'each'
lib/plugin/acts_as_attachment/lib/acts_as_attachable.rb:84:in 'save_attachements'
app/models/attachment.rb:239:in 'attach_files'
app/controllers/file_controller.rb:45:in 'create'

Anybody can help me?
Thanks.