Thanks a lot dear friend mj!
I got another solution too ...seems like now two solutions are available...
here i tried this thing which is working perfectly ...
Try the following:
1. rm /usr/bin/kppp
2. chmod u+s /usr/sbin/kppp
3. ln -s /usr/sbin/kppp /usr/bin/kppp
The first line removes a symbolic link to the real binary. The second line changes the permissions on kppp so that it will run as root no matter what user runs the program. The last line re-creates the link that you removed in the first step. The net effect is that the binary runs as root, no matter what the UID of the user running the program. This means that you don't have to supply a root password.
after this only ting which i neede was to reconfig my kppp .
Thank you mj for your help