Invalid command ‘Header’, perhaps misspelled or defined by a module not included in the server configuration

I got the following error for one of the Magento e-commerce website:

Invalid command ‘Header’, perhaps misspelled or defined by a module not included in the server configuration

After googling it was found that the related headers module was not enabled in Apache.

I was able to fix the issue simply by following two commands:
1. Enabling headers Module

ln -sf /etc/apache2/mods-available/headers.load /etc/apache2/mods-enabled/headers.load

2. Restarting Apache

/etc/init.d/apache2 restart

Note: Above commands were run from Ubuntu 10.04.2 server

Hope this’s helpful.
Cheers