Shahbaz,
Yes, you can backup the database on the Content Distribution Manager as well as the Content Router. Steps to back up this database are located here:
http://www.cisco.com/univercd/cc/td/doc/product/webscale/uce/acns50/cref50/14623ref.htm#3036050
The database backuo image will be made available via FTP after it is generated, and you must login via FTP onto the CDM as the administrator to gain access to this file.
It would probably not make sense to backup the CE's database. If you were to install a new CE, it would negotiate a new secure session key, and then start replicating content to this device. A database backup of the CE does not include the content itself.
To make the restoration of the CE easier, you could set all of your content and channels into a group that are set to auto-subscribe. When the a new or replacement CE is brought on-line, it will automatically fill with the content, and update the database within the CE.
-Ted