Sometime Today, Parul Mathur assembled some asciibets to say:
the type of authentication used by the ISP. The options offered are PAP, CHAP, script-based and terminal-based. My ISP is VSNL and I
VSNL supports PAP, script and terminal. PAP is where the system does authentication through exchange of certain info. script is where you have an expect script read from the line, and write to it in exactly the same way as you would. terminal based is supposed to bring up a terminal for you to type your username and password.
This is what didn't happen, which is why pppd died.
You need to configure it as script-based, and enter required details in your script.
There are easier ways however.
Philip