Sudhirhk
Did you install the free version of Dansguardian as outlined here
http://wiki.contribs.org/Dansguardianor
did you install the dungog commercial version ?
The free version does not have a server manager panel, the commercial version does.
If you are using the free version then please re-read the contrib wiki article more carefully.
All setting changes are made directly to the dansguardian config files and you MUST restart dansguardian after any change in order for the changes to take effect.
It is clearly spelt out in the article.
If you are using the dungog commercial version then many details exist at the dungog website and you are entitled to support from dungog, so ask there.