I'm sorry you're having trouble with your Drupal site. While checking into this, I found that this error usually is triggered when you are in the admin area of Drupal. The file jquery.cookie.js triggers a mod_security rule on the server. To resolve this, there are two options:
1. Request that mod_security be turned of for the site. This can be done by sending an email to firstname.lastname@example.org with the domain name you want mod_security disabled for. Be sure to include either the AMP password or the last 4 digits of the credit card on file for account verification.
2. Using the cPanel File Manager, change the file name jquery.cookie.js to jquery_cookie.js and modify your modules/system/system.module file as follows:
Look for the following code and change misc/jquery.cookie.js to misc/jquery_cookie.js
Please let us know if you have any additional questions or need further assistance.
I had this problem too.
I understand that these two are possible options but I think that the best option would be to change the mod_security rule. It seems from this link that the default rule has changed already in August 2010.
If it is possible this change, I would appreciate.
Thank you for your comment. Unfortunately, on our server, mod_security can only be disabled in a per domain basis in the Modsec Manager. Modsec Rules need to be edited in the httpd.conf file which is not accessible on our servers. Sorry for that.
While the server mod_security rules may be changed at some point during server upgrade or maintenance. it is not something that requires immediate attention. For accounts that are experiencing issues, it is advised that you disable/enable the mod_sec for the cPanel account as needed.