No reason to double reply.......
Have you compared your /etc/pam.d/kppp file to the sample one???? You only need to look at the first line of the sample file;
auth sufficient pam_permit.so
As root using your choice of text editor (nedit, vi, vim, kwrite or whatever), try double clicking in the file to edit.
This should meet your desire;
Now this is not what i want. i want to give the users access to internet but not to root previlages. what should i do.