How to fix Not Acceptable 406 error?

I came across a problem when I was trying to build my website with dede cms script. The steps to produce are:
1: Install dede cms script and setup the parameters for mysql connections.
2: Go to the backend management interface.
3: Type username and password, then click sumbit button to submit the form
4: A following message was given.

Not Acceptable
An appropriate representation of the requested resource /dede/login.php could not be found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/1.3.37 Server at qiquworld.com Port 80

After research, the way to fix the problem is:
Create or edit a text file named .htaccess for website's root directory and add the following code:

<IfModule mod_security.c>
   SecFilterEngine Off
   SecFilterScanPOST Off
</IfModule>