The requested URL /about was not found on this server

It worked for me like this:

Go to Wordpress Admin Dashboard > “Settings” > “Permalinks” > “Common settings”, set the radio button to “Custom Structure” and paste into the text box:

/index.php/%year%/%monthnum%/%day%/%postname%/

and click the Save button.

I got this solution from this link

If all above point not work. Then try this one. I tried it. It's working for me.

1. Go /etc/httpd/conf/httpd.conf.
2. Change the AllowOverride None to AllowOverride All.
3. Restart the apache server.

UPDATE 2017

For new versions of apache the file is called apache2.conf

So to access the file, type sudo nano /etc/apache2/apache2.conf and change the correspondent line inside block <Directory /var/www >

FWIW: I rebuilt a LAMP server from scratch and installed WordPress. I had the same issue after saving my Permalink setting to generate the .htaccess file. Turns out that mod_rewrite was not enabled. I ran across this post on Digital Ocean.
FTA:

First, we need to activate mod_rewrite. It’s available but not enabled with a clean Apache 2 installation.

$ sudo a2enmod rewrite

This will activate the module or alert you that the module is already enabled. To put these changes into effect, restart Apache.

$ sudo systemctl restart apache2

That's not a typical Wordpress rewrite block. This is:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

See http://codex.wordpress.org/Using_Permalinks#Where.27s_my_.htaccess_file.3F

Where's my .htaccess file? WordPress's index.php and .htaccess files should be together in the directory indicated by the Site address (URL) setting on your General Options page. Since the name of the file begins with a dot, the file may not be visible through an FTP client unless you change the preferences of the FTP tool to show all files, including the hidden files. Some hosts (e.g. Godaddy) may not show or allow you to edit .htaccess if you install WordPress through the Godaddy Hosting Connection installation.

Creating and editing (.htaccess) If you do not already have a .htaccess file, create one. If you have shell or ssh access to the server, a simple touch .htaccess command will create the file. If you are using FTP to transfer files, create a file on your local computer, call it 1.htaccess, upload it to the root of your WordPress folder, and then rename it to .htaccess.

You can edit the .htaccess file by FTP, shell, or (possibly) your host's control panel.

The easiest and fastest thing to do it reset your permalinks in Dashboard>>Settings>>Permalinks and make sure .htaccess is writable so WordPress can write the rules itself.

And: are you aware you are calling index.cgi as your default document rather than index.php? That's wrong. Remove index.cgi. Or try removing the whole line, too, because defining a default doc on your server may not be needed.